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.
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.
Subject(s)
Food Demand , Heat Stress Disorders , Food, Genetically Modified , Agriculture , Pollination , Food , Food SupplyABSTRACT
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.
ABSTRACT
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.
ABSTRACT
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.
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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.
ABSTRACT
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.
ABSTRACT
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.