Identification and analysis of AP2/ERF gene family of Panax notoginseng and function of PnDREB84 gene / 药学学报

The AP2/ERF gene family is one of the largest transcription factor families in the plant kingdom, and plays an important role in response to biological and abiotic stresses, plant hormone responses, and plant growth and development. In this study, the AP2/ERF family of Panax notoginseng was identified by bioinformatics methods, and the physicochemical properties, structure, phylogenetic relationship, expression pattern and function of PnDREB4 gene of the family were analyzed. The results showed that 140 AP2/ERF family members were identified in P. notoginseng, which were divided into DREB, ERF, AP2, RAV and Sololit subgroups. The physicochemical properties and motifs of proteins were similar among the subgroups. There were 34 differentially expressed genes in the AP2/ERF family of Fusarium oxysporum infected P. notoginseng plants, and 19 genes were up-regulated. The expression level of PnDREB84 was up-regulated with the extension of Fusarium oxysporum infection time in the range of 0-96 h. The content of ABA and SA in P. notoginseng plants overexpressing PnDREB84 gene increased after 4 ℃ stress. The results showed that PnDREB84 gene plays a dual regulatory role in the process of biological stress and abiotic stress. PnDREB84 gene can be used as a potential molecular marker for the breeding of new varieties of P. notoginseng. The identification of AP2/ERF transcription factor and function analysis of PnDREB84 gene of P. notoginseng provided data support for the analysis of stress resistance mechanism of P. notoginseng and the breeding of new varieties.

Response and tolerance mechanism of food crops under high temperature stress: a review / Mecanismo de resposta e tolerância de culturas alimentares sob estresse de alta temperatura: uma revisão

High temperature stress events are critical factors inhibiting crop yield. Meanwhile, world population is growing very rapidly and will be reached up to 9 billion by 2050. To feed increasing world population, it is challenging task to increase about 70% global food productions. Food crops have significant contribution toward global food demand and food security. However, consequences from increasing heat stress events are demolishing their abilities to survive and sustain yield when subjected to extreme high temperature stress. Therefore, there is dire need to better understand response and tolerance mechanism of food crops following exposure to heat stress. Here, we aimed to provide recent update on impact of high temperature stress on crop yield of food crops, pollination, pollinators, and novel strategies for improving tolerance of food crop under high temperature stress. Importantly, development of heat-resistant transgenic food crops can grant food security through transformation of superior genes into current germplasm, which are associated with various signaling pathways as well as epigenetic regulation in response to extreme high temperature stress.

Eventos de estresse de alta temperatura são fatores críticos que inibem o rendimento das culturas. Enquanto isso, a população mundial está crescendo muito rapidamente e atingirá até 9 bilhões em 2050. Para alimentar a crescente população mundial, é uma tarefa desafiadora aumentar cerca de 70% da produção global de alimentos. As culturas alimentares têm uma contribuição significativa para a procura global de alimentos e a segurança alimentar. No entanto, as consequências do aumento de eventos de estresse por calor estão destruindo suas habilidades de sobreviver e manter a produção quando submetidos a estresse de alta temperatura. Portanto, há uma necessidade urgente de entender melhor o mecanismo de resposta e tolerância das safras de alimentos após a exposição ao estresse por calor. Aqui, nosso objetivo foi fornecer atualizações recentes sobre o impacto do estresse de alta temperatura no rendimento de culturas de alimentos, polinização, polinizadores e novas estratégias para melhorar a tolerância de culturas de alimentos sob estresse de alta temperatura. É importante ressaltar que o desenvolvimento de culturas alimentares transgênicas resistentes ao calor pode garantir segurança alimentar por meio da transformação de genes superiores em germoplasma atual, que estão associados a várias vias de sinalização, bem como à regulação epigenética em resposta ao estresse de alta temperatura extrema.

Response and tolerance mechanism of food crops under high temperature stress: a review

Abstract High temperature stress events are critical factors inhibiting crop yield. Meanwhile, world population is growing very rapidly and will be reached up to 9 billion by 2050. To feed increasing world population, it is challenging task to increase about 70% global food productions. Food crops have significant contribution toward global food demand and food security. However, consequences from increasing heat stress events are demolishing their abilities to survive and sustain yield when subjected to extreme high temperature stress. Therefore, there is dire need to better understand response and tolerance mechanism of food crops following exposure to heat stress. Here, we aimed to provide recent update on impact of high temperature stress on crop yield of food crops, pollination, pollinators, and novel strategies for improving tolerance of food crop under high temperature stress. Importantly, development of heat-resistant transgenic food crops can grant food security through transformation of superior genes into current germplasm, which are associated with various signaling pathways as well as epigenetic regulation in response to extreme high temperature stress.

Resumo Eventos de estresse de alta temperatura são fatores críticos que inibem o rendimento das culturas. Enquanto isso, a população mundial está crescendo muito rapidamente e atingirá até 9 bilhões em 2050. Para alimentar a crescente população mundial, é uma tarefa desafiadora aumentar cerca de 70% da produção global de alimentos. As culturas alimentares têm uma contribuição significativa para a procura global de alimentos e a segurança alimentar. No entanto, as consequências do aumento de eventos de estresse por calor estão destruindo suas habilidades de sobreviver e manter a produção quando submetidos a estresse de alta temperatura. Portanto, há uma necessidade urgente de entender melhor o mecanismo de resposta e tolerância das safras de alimentos após a exposição ao estresse por calor. Aqui, nosso objetivo foi fornecer atualizações recentes sobre o impacto do estresse de alta temperatura no rendimento de culturas de alimentos, polinização, polinizadores e novas estratégias para melhorar a tolerância de culturas de alimentos sob estresse de alta temperatura. É importante ressaltar que o desenvolvimento de culturas alimentares transgênicas resistentes ao calor pode garantir segurança alimentar por meio da transformação de genes superiores em germoplasma atual, que estão associados a várias vias de sinalização, bem como à regulação epigenética em resposta ao estresse de alta temperatura extrema.

Advances in the physiological functions of plant lipids in response to stresses / 生物工程学报

Lipids are important components of living organisms that participate in and regulate a variety of life activities. Lipids in plants also play important physiological functions in response to a variety of abiotic stresses (e.g. salt stress, drought stress, temperature stress). However, most research on lipids focused on animal cells and medical fields, while the functions of lipids in plants were overlooked. With the rapid development of "omics" technologies and biotechnology, the lipidomics has received much attention in recent years because it can reveal the composition and function of lipids in a deep and comprehensive way. This review summarizes the recent advances in the functions and classification of lipids, the development of lipidomics technology, and the responses of plant lipids against drought stress, salt stress and temperature stress. In addition, challenges and prospects were proposed for future lipidomics research and further exploration of the physiological functions of lipids in plant stress resistance.

Transcriptional memory and response to adverse temperatures in plants / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Temperature is one of the major environmental signals controlling plant development, geographical distribution, and seasonal behavior. Plants perceive adverse temperatures, such as high, low, and freezing temperatures, as stressful signals that can cause physiological defects and even death. As sessile organisms, plants have evolved sophisticated mechanisms to adapt to recurring stressful environments through changing gene expression or transcriptional reprogramming. Transcriptional memory refers to the ability of primed plants to remember previously experienced stress and acquire enhanced tolerance to similar or different stresses. Epigenetic modifications mediate transcriptional memory and play a key role in adapting to adverse temperatures. Understanding the mechanisms of the formation, maintenance, and resetting of stress-induced transcriptional memory will not only enable us to understand why there is a trade-off between plant defense and growth, but also provide a theoretical basis for generating stress-tolerant crops optimized for future climate change. In this review, we summarize recent advances in dissecting the mechanisms of plant transcriptional memory in response to adverse temperatures, based mainly on studies of the model plant

Effects of High Temperature Stress on Growth Characteristics of Armillaria / 中国实验方剂学杂志

Objective:To explore the effects of high temperature stress on the growth characteristics of different Armillaria strains，and to provide guidance for screening excellent Armillaria strains with high-temperature resistance. Method:14 strains of Armillaria from different G. elata producing areas were used as experimental materials to observe the growth characteristics and conduct phenotypic classification for the strains. rDNA-IGS sequence analysis was used for molecular identification to further determine the genetic relationship of the tested strains.The strain growth rate, biomass，mycelial length and other indicators under the condition of 23 ℃ （CK） and 30 ℃ high temperature stress were recorded. Result:All the 14 strains of Armillaria had the highest similarity and the closest relationship with Armillaria gallica，but there were significant differences in growth characteristics among different G. elata producing areas. The 14 strains of Armillaria were classified into Ⅳ groups，and the growth status was groupⅠ>group Ⅱ>group Ⅲ>group Ⅳ. After treatment with high temperature stress，the tolerance of each strain to high temperature also showed obvious differences，as shown in the average growth rate of the mycelial was GZ16>SX1>GZ1. The rank of relative mycelial length was GZ16>SX1>GZ3 and the relative biomass was GZ16>SX4>GZ1>HB1>AH2. Conclusion:Under high temperature stress，GZ16 was best in growth rate，relative length of mycelial，relative biomass and growth state，followed by SX1 and GZ1 strains. The results indicate that strains GZ16，SX1 and GZ1 have the strong resistance to high temperature and excellent growth characteristics at normal temperature，so these three strains are suitable to be produced in main G. elata producing areas in China.

Cloning and function analysis of elongase of very long chain fatty acid gene Bmelo424 in silkworm / 生物工程学报

Genes belonging to the elongases of very long chain fatty acid (ELOVL) family affect many physiological functions in organism. In this paper, Bmelo424 gene, a member of the ELOVL family in silkworm, was cloned and its ORF was 558 bp. Its protein sequence was predicted to have four transmembrane domains, six serine phosphorylation sites, eight threonine phosphorylation sites and four tyrosine phosphorylation sites, and its subcellular localization was in the endoplasmic reticulum. Secondary structure analysis showed that the percentage of alpha-helix and beta-strand was 26.7% and 20% respectively. The results of fluorescence quantitative PCR showed that Bmelo424 gene was expressed in all tissues of silkworm, especially with the highest expression in head. By heterologous expression of Bmelo424 gene in Saccharomyces cerevisiae, the effect of Bmelo424 gene on fatty acid elongation was studied. GC-MS results indicated that the fatty acid content of C16:1n-7 in S. cerevisiae with pYES2-Bmelo424 recombinant plasmid increased significantly, whereas the content of C16:0, C18:0 and C18:1n-9 decreased. The results of temperature stress revealed that Bmelo424 gene could improve the low temperature adaptability of S. cerevisiae, but its high temperature adaptability decreased. This provides a reference for exploring the function of Bmelo424 gene in silkworm.

Study of exogenous uniconazole on alleviating low-temperatuer stress of coix seedlings / 中国中药杂志

The aim of the study is to explore exogenous S3307 on alleviating low-temperature stress of coix seedlings. The coix cultivar, "No 5 Yiliao", was selected as the plant material, through nutrient solution cultivating in greenhouse, the effect of different S3307 concentrations(1, 3, 5, 7, 9 mg·L~(-1)) on coix seedlings traits and physiological indicators were explored under low-temperature stress. The results showed, under low-temperature 5 mg·L~(-1) S3307 could significantly increase coix seedlings stem diameter and biomass, which stem diameter and above-ground biomass, low-ground biomass separately were enhanced 11.90%, 13.59%, 10.99%. Leaf width and lateral root number separately were enhanced 7.63%, 37.52%. Meanwhile, addition of 5 mg·L~(-1) S3307 could significantly reduce relative conductivity and MDA, separately being reduced 23.33%, 17.42% compared to CKL. S3307 could also significantly increase soluble sugar and proline content, which leaf soluble sugar and proline content separately were enhanced 17.16%, 11.87%, which root soluble sugar and proline content separately were enhanced 20.00%, 33.42%. Additionally, S3307 could alleviate the cells destroy in ultra-structure level by improving cell membrane structure and chloroplast capsule layer structure. 5 mg·L~(-1) S3307 could enhance the low temperature tolerance of coix seedlings by regulating the growth and physiological indexes, and thus alleviate the damage caused by low-temperature to the coix seedlings.

Regulation of extracellular ATP onchlorophyll content and fluorescence characteristics of Angelica sinensis seedlings under drought and low temperature stress / 中国中药杂志

As an important signal molecule, extracellular ATP(eATP) can regulate many physiological and biochemical responses to plant stress. In this study, the regulation of extracellular ATP(eATP) on chlorophyll content and chlorophyll fluorescence parameters of Angelica sinensis seedlings were studied under drought and low temperature stress. The results showed that all the chlorophyll content, the actual photochemical efficiency [Y(Ⅱ)], the electron transfer rate(ETR), the photochemical quenching coefficient(qP and qL) of A. sinensis leaves were significantly decreased under drought and low temperature stress, respectively. At the same time, non-photochemical quenching(NPQ and qN) were also all significantly increased, respectively. The application of eATP alleviated the decrease of chlorophyll content, Y(Ⅱ), ETR, qP and qL of A. sinensis leaves under drought and low temperature stress, and eliminated the increase of qN and NPQ. The results indicated that eATP could effectively increase the open ratio of PSⅡ reaction centers, and improve the electron transfer rate and light energy conversion efficiency of PSⅡ of A. sinensis leaves under drought and low temperature stress. It is beneficial to enhance the chlorophyll synthesis and the adaptability of PSⅡ about A. sinensis seedlings to drought and low temperature stress.

Thermal effect of acute and chronic stress on hepatic and renal tissue of the pacific sardine, Sardinops sagax caeruleus (Jenyns, 1842) / Efecto del estrés térmico agudo y crónico sobre el tejido hepático y renal de la sardina del pacífico, Sardinops sagax caeruleus (Jenyns, 1842)

SUMMARY: In the thermal range of the Pacific waters, known for the geographical distribution of Sardinops sagax caeruleus(Jenyns, 1842) (Pacific sardine), could be exposed to a stressing temperature environment with dilated effect. This work examines the liver and kidney of sardines acclimated at different temperatures and exposed to the lethal temperature and critical thermal maximum trials. The liver and kidney tissues of Sardinops sagax caeruleus acclimated for 25 days at 19, 21, 23 and 25 °C were anatomically examined after exposure to acute heat stress (AHS) caused by increasing the water temperature at a rate of 1 °C per min, and the chronic heat stress (CHS) effect by abruptly exposure to constant water temperature different from that of acclimation (AT). We observed in fish exposed to AHS that the liver tissue had vacuolated or necrotic hepatocytes and infiltration of inflammatory blood cells (25 °C) and the kidney tissue showed degenerative changes in the glomeruli and renal tubules and increased melanomacrophage centers. The CHS effect in liver and renal tissues produced damage signs of pyknosis, apoptosis, necrotic areas, and an increase in melanomacrophage centers as well as outbreaks of bacterial infection. The results demonstrate that S. sagax caeruleus did not tolerate an abrupt thermal change of more than 4 °C, independently of the ATs, over 50 % died. The consequences of the experimental acute and chronic thermal stress were histopathological alterations of liver and kidney. It was expected that the chronic stress temperature could produce in fish conspicuous histological changes, and indeed it was the most deleterious.

RESUMEN: En el rango térmico de las aguas del Pacífico, conocido por la distribución geográfica de Sardinops sagax caeruleus (Jenyns, 1842) (sardina del Pacífico), esta especie podría estar expuesta a un ambiente de temperatura estresante con efecto dilatado. Este trabajo examina el hígado y el riñón de las sardinas aclimatadas a diferentes temperaturas y expuestas a la temperaturas letales y crítica máxima. Los tejidos hepático y renal de Sardinops sagax caeruleus aclimatadas durante 25 días a 19, 21, 23 y 25 °C se examinaron anatómicamente después de la exposición al estrés de calor agudo (AHS) causado por el aumento de la temperatura del agua a una velocidad de 1 °C por minuto, y el efecto de estrés de calor crónico (CHS) por la exposición brusca a una temperatura constante del agua diferente a la de la aclimatación (AT). Observamos en peces expuestos a AHS que el tejido hepático tenía hepatocitos vacuolados o necróticos y la infiltración de células sanguíneas (25 °C) y el tejido renal presentaba cambios degenerativos en los glomérulos y túbulos renales y aumento de centros de melanomacrófagos. El efecto CHS en los tejidos hepático y renal produjo signos de daño de picnosis, apoptosis, áreas necróticas y un aumento en los centros de melanomacrófagos, así como brotes de infección bacteriana. Los resultados demuestran que S. sagax caeruleus no toleró un cambio térmico abrupto de más de 4 °C, independientemente de las AT, más del 50 % murió. Las consecuencias del estrés térmico agudo y crónico experimental fueron las alteraciones histopatológicas del hígado y el riñón. Se esperaba que la temperatura de estrés crónica pudiera producir cambios histológicos conspicuos en los peces, y de hecho fue la más perjudicial.

Enhanced single-cell oil production by cold shock in cyanobacterial cultures / Aumento da produção de óleos unicelulares através de choques de frio em culturas de cianobactérias

ABSTRACT: The aim of this research was to evaluate the enhanced single-cell oil production by cold shock in Aphanothece microscopica Nägeli using dairy processing wastewater as culture medium. The study focused on (i) temperature optimization for biomass production, (ii) cold shock application to induce lipids biosynthesis and (iii) determination of fatty acids profile under different conditions. Results indicated that temperature of 20°C was the best condition in terms of kinetics parameter, reaching biomass productivities of 160.25mg/L.h. Under these conditions, a lipid content of 12.65% was also observed, resulting in a lipid productivity of 20.27mg/L.h. Additionally, the 0°C cold shock was the most efficient in increasing intracellular lipid content, reaching 28.4% in dry weight. Cold shocks also showed influence on the saturation of fatty acid composition, where the saturated fatty acids decreased, and the monounsaturated and polyunsaturated fatty acids increased by increasing the cold application. Thus, the use of cold shocks indicates to be a key condition for improving the prospects of efficient single-cell oils production.

RESUMO: O objetivo deste trabalho foi avaliar o aumento da produção de óleos unicelulares por Aphanothece microscopica Nägeli utilizando água residuária de processamento de laticínios como meio de cultura. O estudo concentrou-se na (i) otimização da temperatura para produção de biomassa, (ii) aplicação de choque frio para induzir a biossíntese de lipídios e (iii) determinação do perfil de ácidos graxos sob diferentes condições. Os resultados indicam que a temperatura de 20°C foi a melhor condição em termos de parâmetros cinéticos, atingindo produtividades de biomassa de 160,25mg/L.h. Nesta condição também foi observado um teor lipídico de 12,65%, o que resultou em uma produtividade lipídica de 20,27mg/L.h. Além disso, o choque frio de 0°C foi o mais eficiente para aumentar o conteúdo lipídico intracelular, que atingiu 28,4% em peso seco. Os choques frios também mostraram influência na saturação da composição de ácidos graxos, em que os ácidos graxos saturados diminuíram, e os ácidos graxos monoinsaturados e poli-insaturados ampliaram com o aumento da aplicação de frio. Assim, o uso de choques frios indica ser uma condição chave para melhorar as perspectivas de produção eficiente de óleos unicelulares.

Effects of high temperature stress on physiological indicators of Paris polyphylla var. yunnanensis / 中草药

Objective To provide a reference for the introduction and cultivation of Paris polyphylla var. yunnanensis in mid-south region of China, its resistance adaptation ability of high temperature was explored. Methods Strong seedlings of P. polyphylla var. yunnanensis were chosen and treated under different temperature conditions (25 ℃/20 ℃, 33 ℃/28 ℃, 39 ℃/34 ℃) for 7 d, and then investigated the effect on their related physiological indexes. Results The results showed that with the increase of temperature and stress time, the relative water content of the leaves of P. polyphylla var. yunnanensis decreased significantly under the treatment of 33 ℃/28 ℃ and 39 ℃/34 ℃ for 7 d, which was 17.38% and 58.25% lower than the control (25 ℃/20 ℃) respectively. The relative conductivity and the content of malondialdehyde (MDA) were both increased continuously, and it was respectively 3.59 times and 2.55 times higher than that of control under the temperature of 39 ℃/34 ℃. The content of soluble sugar decreased gradually at 39 ℃/34 ℃, which was 33.25% lower than that of the control. The changing of soluble protein content showed a wavy trend, and the fluctuation range of 33 ℃/28 ℃ treatment groups was larger than that of the control group, which increased to 1.32 times of the control after 7 d. The SOD increased firstly and then decreased. The peak value was reached after 4 d at 39 ℃/34 ℃, which was 2.35 times higher than that of the control group. The POD increased gradually in treatment group, which increased to 2.33 times of that in control group at 39 ℃/34 ℃ for 4 d, and the amplitude of the change gradually slowed down. Conclusion In the experimental temperature range, P. polyphylla var. yunnanensis grew well at 25 ℃/20 ℃, which was its optimal growth temperature. Long-term continuous temperature stress treatment at 33 ℃/28 ℃ can cause damage to plant leaves; High temperature at 39 ℃/34 ℃ will seriously damage the physiological and morphological structure of the plant, and even lead to the death of the plant.

Genetic transformation of the Brazilian BR 451 maize variety by the Agrobacterium tumefaciens method / Transformação genética da variedade brasileira de milho BR 451 pelo método da Agrobacterium tumefaciens

ABSTRACT: The asexually gene introduction by genetic engineering has brought enormous possibilities to innovate plant breeding. However, principally because of the low in vitro response, genetic transformation has been restricted to only certain genotypes of agronomically significant species. With the objective of establishing a protocol for genetically transforming the Brazilian BR 451 maize variety through Agrobacterium tumefaciens, it was studied the capacity of plant regeneration in vitro from embryogenic calli cultivated in three regeneration media, each having different growth regulators. It was also evaluated the temperature stress effect on the transformation of the immature embryos with A. tumefaciens EHA 101 containing the plasmid pTF102 with uidA and bar genes. The BR 451 variety embryos and those of the Hi-II hybrid (control) were exposed to three treatments applied as they were being infected with the agrobacteria (a) infection at 25°C; (b) infection at 40°C; (c) pretreatment at 40°C for 5 seconds followed by infection at 25°C. Transformation was determined by uidA gene expression and through the callus resistant to the herbicide Bialaphos® formation. Embryos infected at 40°C showed a higher degree of genetic transformation in the Hi-II, although the same was not noted in BR 451. When growth regulators were added to the culture medium the number of regenerated BR 451 plants showed no increase.

RESUMO: A introdução de genes de forma assexual por meio da engenharia genética tem ampliado as possibilidades do melhoramento genético vegetal. No entanto, devido principalmente a baixa resposta in vitro, a transformação genética tem se limitado a poucos genótipos das espécies de interesse agronômico. Visando estabelecer protocolo de transformação genética da variedade de milho BR 451 via Agrobacterium tumefaciens, foi estudada a capacidade de regeneração de plantas in vitro a partir de calos embriogênicos cultivados em três meios de regeneração contendo diferentes reguladores de crescimento. Também foi avaliado o efeito do estresse de temperatura na transformação de embriões imaturos com a A. tumefaciens EHA 101portadora do plasmídeo pTF102 que contém os genes uidA e bar. Para tal, três tratamentos foram aplicados aos embriões da variedade BR 451 e do híbrido Hi-II (controle) durante a infecção com a agrobactéria: (a) infecção em 25oC; (b) infecção a 40oC; (c) pré-tratamento de 40oC por cinco segundos seguido por infecção em 25oC. A transformação foi avaliada mediante a expressão do gene uidA e a formação de calos resistentes ao herbicida Bialaphos®. A infecção de embriões a 40oC aumentou a transformação genética em Hi-II, mas não em BR 451. A adição de reguladores de crescimento no meio de regeneração não incrementou o número de plantas regeneradas.

Correlation between Expression of LEA2 Gene from Gastrodia elata and Cold Resistance / 中国药学杂志

OBJECTIVE: To find out the correlation between LEA2 gene from Gastrodia elata and cold resistance. METHODS: Two LEA2 cDNA sequences were obtained by screening the transcriptome of seeds from Gastrodia elata. Recombinant plasmid was obtained and imported into Escherichia coli. Then the transformed Escherichia coli(pET28a-LEA2) received low temperature treatment. RESULTS: GeLEA2-1 had a complete 477 bp ORF encoding 158 amino acids and its molecular weight was 17.3×103. In addition, GeLEA2-2 had a complete 942 bp ORF encoding 313 amino acids and its molecular weight was 34.85×103. Phylogenetic analysis showed the two GeLEA2 were highly homologous with LEA2 from Arabidopsis thaliana and Oryza sativa. The growth curves of E. coli BL21(DE3) showed that the strain expressing GeLEA2 tolerated low temperature more poorly than the control. CONCLUSION: Our work reveals that GeLEA2 could response to low temperature stress by negative regulation.

Cloning and expression analysis of WRKY5 gene in Dendrobium officinale / 中草药

Objective: In order to isolate and analysize the bioinformatics and expression pattern of DoWRKY5 gene from Dendrobium officinale. Methods: A WRKY gene was first obtained by transcriptome sequencing and reverse transcription-polymerase chain reaction (RT-PCR) from D. officinale and analyzed by bioinformatics tools. The tissue expression pattern and the low temperature stress, abscisic acid (ABA) stress, and sucrose stress responses were analyzed by qRT-PCR. Results: The cDNA sequence of DoWRKY5 gene was isolated, which was 1 336 bp in length, with an open reading frame (ORF) of 834 bp and an encoded polypeptide of 277 amino acid. The amino acid sequence contained a conserved WRKY domains and a zinc finger structures (C2H2), belonging to Group II of WRKY family. Expression analysis by qRT-PCR showed that DoWRKY5 was expressed in the roots, stems, and leaves of D. officinale, and the most abundant in leaves. The amount of DoWRKY5 expression were significantly increased under low temperature of 4℃ and different time. Moreover, the expression of DoWRKY5 could be induced by ABA and source. Conclusion: DoWRKY5 may be an important transcription factor to response cold stress and other abiotic stresses in D. officinale, which provides a foundation for further study of cold tolerance mechanism and cold-resistant breeding of D. officinale.

Effect of MeJA combined with high temperature stress in treatment for accumulation of triterpenoids in birch suspension cells / 中草药

Objective: To investigate the effect of MeJA combined with high temperature stress in the treatment for the accumulation of triterpenoids in the birch (Betula platyphylla) suspension cells. Methods: After MeJA (25, 50, 100, and 150 μmol/L)and high temperature (50℃ for 2 h) treatment, the cell growth, viability, content of MDA, the activity of defense enzyme, total triterpenoids content, and the gene expression levels of triterpenoids synthesis were measured. Results: The combination of high temperature stress and MeJA treatment had a more powerful positive effect on the synthesis of triterpenoids than single MeJA or high temperature treatment in birch cells. Moreover, the concentration of total triterpenoids had the highest level when adding 150 μmol/L MeJA after the high temperature processing, was up to 76.6 mg/g, which was 81.3%, 159.9% and 13.1% higher than those in the blank control, individual MeJA treatment or the heat treatment alone respectively. Meanwhile, the gene expression levels of SS, SE, BPW, and BPY, related to the triterpenoids synthesis, had an increase about 297.1%, 83.7%, 1 032.6%, and 282.4% compare to the control. The MeJA after high temperature treatment enhanced the activity of SOD and PAL compared with the control, inhibited the cell growth and viability. Conclusion: The treatment of MeJA after high temperature affects the cell growth, viability, and activity of defense enzyme, regulates the genes expression level of triterpenoids synthesis, and eventually could make cells to produce the triterpenoids substance effectively.

Effects of high temperature stress on plasma membrane permeability and chloroplast structure of Huperzia serrata / 中草药

Objective: Huperzia serrata, whose growth is limited by high temperature, is a rare medicinal plant with the treatment function for Alzheimer's disease (AD). To research the effect of high temperature on the structure and function of cell membrane and chloroplast, and to provide the evidence for production practices. Methods: H. serrata was processed at 25, 30, 35, and 40°C, respectively, then the content changes of malondial dehyde (MDA) and conductivity rate, and the content changes of total chlorophyll, chlorophyll a, chlorophyll b, and chlorophyll a/b values were measured. The changes of the chloroplast ultra microstructure were observed under the transmission electron microscope (TEM). Results: The changes of MDA and conductivity rate in the process at 35 and 40°C were significantly higher than those of the control group; After processed at 40°C for 4 d, the total chlorophyll was decreased significantly, and became the lowest on the day 6, just was 58% compared to the control group; the change trends to the contents of chlorophyll a, chlorophyll b, and total chlorophyll were similar; TEM observation revealed that after processed at 35°C for 4 d, the chloroplast structure appeared deformation, and after processed at 40°C for 4 d, the chloroplast structure subjected obvious destruction capsule fuzzy, fracture in different degrees, thylakoid in disorder, matrix lamellar irregular, and so on. Conclusion: According to the changes of physiological index, ultramicroscopic structure, and external morphology of chloroplast, the suitable temperature for H. serrata is 25-30°C, 40°C is the limited temperature, causing death after 4 d stress, and 35°C has obvious impact on the growth, long-time stress in 35°C could also cause plant deaths.

Nitric oxide alleviates oxidative damage induced by high temperature stress in wheat.

Effect of sodium nitroprusside (SNP), a donor of nitric oxide (NO) was examined in two wheat (Triticum aestivum L.) cultivars, C 306 (heat tolerant) and PBW 550 (comparatively heat susceptible) to study the extent of oxidative injury and activities of antioxidant enzyme in relation to high temperature (HT) stress. HT stress resulted in a marked decrease in membrane thermostability (MTS) and 2, 3, 5-triphenyl tetrazolium chloride (TTC) cell viability whereas content of lipid peroxide increased in both the cultivars. The tolerant cultivar C 306 registered less damage to cellular membranes compared to PBW 550 under HT stress. Activities of antioxidant enzymes viz, superoxide dismutase, catalase, ascorbate peroxidase, guaicol peroxidase and glutathione reductase increased with HT in both the cultivars. Following treatment with SNP, activities of all antioxidant enzymes further increased in correspondence with an increase in MTS and TTC. Apparently, lipid peroxide content was reduced by SNP more in shoots of heat tolerant cultivar C 306 indicating better protection over roots under HT stress. The up-regulation of the antioxidant system by NO possibly contributed to better tolerance against HT induced oxidative damage in wheat.

Impact of temperature on heat shock protein expression of Bombyx mori cross-breed and effect on commercial traits.

The present study investigated the effect of increasing temperature stress on the thermotolerance of B. mori crossbreed PM x CSR2 and tissue specific differential expression of heat shock proteins at IVth and Vth instars. The larvae reared at 25 ± 1oC and 70 ± 5% relative humidity were treated as control. Larvae were subjected to heat shock temperatures of 34, 38 and 42oC for 3 hr followed by 3 hr recovery. Expression of Heat shock protein 72 were analyzed by SDS-PAGE and confirmed by western blotting analysis. The impact of heat shock on commercial traits of cocoons was analyzed by following different strategies in terms of acquired thermotolerance over control. Resistance to heat shock was increased as larval development proceeds and increased thermotolerance is achieved with the induction of Heat shock protein 72 in the Vth instar larval haemolymph. Relative influence of heat shock temperatures on commercial traits corresponding to the generation of heat shock protein 72 was significantly improved over control. In PM x CSR2, cocoon and shell weight significantly increased to 9.90 and 11.90% over control respectively.

Stress response in pathogenic bacteria.

Bacterial pathogens survive under two entirely different conditions, namely, their natural environment and in their hosts. Response of these pathogens to stresses encountered during transition from the natural environment to human hosts has been described. The virulence determinants of pathogenic bacteria are under the control of transcriptional activators which respond to fluctuations in growth temperature, osmolarity, metal ion concentration and oxygen tension of the environment. The regulation of stress induced genes may occur at the level of transcription or translation or by post-translational modifications. Under certain stress conditions local changes in the superhelicity of DNA induce or repress genes. In addition to their role in survival of bacteria under stressful situations, the stress induced proteins are also implicated in the manifestation of pathogenicity of bacterial pathogens in vivo.