Characterization and transformation of TtMYB1 transcription factor from Tritipyrum to improve salt tolerance in wheat.

BACKGROUND: Common wheat (Triticum aestivum L.) is a worldwide cereal crop, which is an integral part of the diets of many countries. In addition, the MYB gene of wheat plays a role in the response to salt stress. RESULTS: "Y1805" is a Tritipyrum variety that is relatively tolerant to salt. We used transcriptome analysis to show that the "Y1805" MYB gene was both highly expressed and sensitive to salt stress. Compared with control roots, the level of MYB expression during salt stress was higher, which rapidly decreased to control levels during the recovery process. MYB gene relative expression showed the highest levels in "Y1805" roots during salt stress, with the stems and then leaves being the next highest stressed tissues. The novel MYB gene (TtMYB1) was successfully cloned from "Y1805". It showed a coding sequence length of 783 bp with 95.79% homology with Tel2E01G633100 from Thinopyrum elongatum. TtMYB1 and MYB from Th. elongatum were clustered in the same branch using phylogenetic analysis, which indicated high similarities. The TtMYB1 gene is located in the nucleus. The coleoptile method was employed when a TtMYB1 overexpression vector was used during transformation into "1718" (common wheat). Under high salt stress, TtMYB1 leaves of overexpression lines had decreased wilting, when compared with wild-type (WT) plants. During normal conditions, salt stress, and recovery, the lengths of the roots and the heights of seedlings from the overexpression lines were found to be significantly greater than roots and seedlings of WT plants. In addition, during high salt stress, the overexpression lines showed that proline and soluble sugar levels were higher than that of WT plants, but with lower malondialdehyde levels. Forty-three proteins that interacted with TtMYB1 were identified using the yeast two-hybrid assay. Protein-protein interaction analyses indicated that most were SANT domain-containing and Wd repeat region domain-containing proteins. Among these proteins, ribosomal proteins were the main node. Abiotic stress-related terms (such as "carbonate dehydratase activity", "protein targeting peroxisomes", and "glutathione peroxidase activity") were enriched in GO analysis. In KEGG analysis, "carbohydrate metabolism", "environmental information processing", "genetic information processing", "signaling and cell precursors", and "energy metabolism" pathways were enriched. CONCLUSION: The TtMYB1 gene might enhance salt tolerance by increasing proline and soluble sugar content and antioxidase activity in transgenic wheat. It therefore has the potential to enhance high salt tolerance in plants.

Characterization and transformation of the CabHLH18 gene from hot pepper to enhance waterlogging tolerance.

Basic helix-loop-helix (bHLH) proteins are important in abiotic stress control. Here, a specific bHLH transcription factor gene, CabHLH18, from a strong waterlogging-tolerant pepper cultivar, 'ZHC2', was successfully cloned. The CabHLH18 gene presented a coding sequence length of 1,056 bp, encoding 352 amino acids, and the protein was the closest to Capsicum annuum XM016694561.2 protein. The CabHLH18 protein was located in the nucleus. The transformation of the CabHLH18 overexpression vector into the plumules of hot peppers, 'DFZJ' and 'ZHC1', exhibited 21.37% and 22.20% efficiency, respectively. The root length, plant height, and fresh weight of the 'DFZJ' overexpression lines were greater than those of wild-type (WT) plants under waterlogging conditions. Compared with the WT plants, the overexpression lines generally showed greater contents of water, the amino acid, proline, soluble sugar, root viability, and superoxide dismutase activity, but lower malondialdehyde content under waterlogging conditions. Plant fresh weight, amino acids, proline, and soluble sugar levels of the overexpression lines were 39.17%, 45.03%, 60.67%, and 120.18% greater, respectively, compared with the WT plants at 24 h after waterlogging stress. Therefore, the CabHLH18 gene could be implicated in conferring waterlogging tolerance in hot peppers and holds promise for enhancing their overall waterlogging tolerance.

Integrative proteomic and physiological analyses of the molecular response to dessication-stress in Auricularia fibrillifera.

Drought stress is one of the main factors influencing the growth and development of an organism. Auricularia fibrillifera has strong dessication resistance. In A. fibrillifera under dessication-stress, the melanin content of fruiting bodies elevated significantly by >10-fold compared with the control. Folate content also increased sharply but decreased significantly after rehydration, and amino acid and biotin levels increased by 40.11 and 22.14%, respectively. In proteomic analysis, 1,572 and 21 differentially abundant proteins (DAPs) were identified under dessication-stress and rehydration, respectively. A large number of DAPs were annotated in "amino acid metabolism," "carbohydrate metabolism," and "translation" pathways, and the DAPs related to osmotic regulation and antioxidant enzymes were significantly increased in abundance. Transcriptome-proteome association analysis showed that most DAPs (30) were annotated in the "biosynthesis of antibiotics" pathway. DAPs and corresponding differentially expressed genes were all up-regulated in the "biotin biosynthesis" pathway and associated with "folate biosynthesis" and "phenylalanine, tyrosine, and tryptophan biosynthesis." In the analysis of protein-protein interactions, the DAPs annotated in the "phenylalanine, tyrosine, and tryptophan biosynthesis" pathway had the strongest interactions with other DAPs. These enriched pathways could enhance amino acid, folate, biotin, and melanin levels during desiccation stress, which is consistent with the physiological data (amino acid, folate, biotin, and melanin contents). In addition, many DAPs related to the cytoskeleton were significantly increased in abundance under dessication-stress. Physiological and transcriptome data were in agreement with proteomic results. This work provides valuable insight into the dessication-tolerant mechanisms of A. fibrillifera.

Characterization of a Novel TtLEA2 Gene From Tritipyrum and Its Transformation in Wheat to Enhance Salt Tolerance.

Late embryogenesis-abundant (LEA) proteins are critical in helping plants cope with salt stress. "Y1805" is a salt-tolerant Tritipyrum. We identified a "Y1805"-specific LEA gene that was expressed highly and sensitively under salt stress using transcriptome analysis. The novel group 2 LEA gene (TtLEA2-1) was cloned from "Y1805." TtLEA2-1 contained a 453 bp open reading frame encoding an 151-amino-acid protein that showed maximum sequence identity (77.00%) with Thinopyrum elongatum by phylogenetic analysis. It was mainly found to be expressed highly in the roots by qRT-PCR analysis and was located in the whole cell. Forty-eight candidate proteins believed to interact with TtLEA2-1 were confirmed by yeast two-hybrid analysis. These interacting proteins were mainly enriched in "environmental information processing," "glycan biosynthesis and metabolism," and "carbohydrate metabolism." Protein-protein interaction analysis indicated that the translation-related 40S ribosomal protein SA was the central node. An efficient wheat transformation system has been established. A coleoptile length of 2 cm, an Agrobacteria cell density of 0.55-0.60 OD600, and 15 KPa vacuum pressure were ideal for common wheat transformation, with an efficiency of up to 43.15%. Overexpression of TaLEA2-1 in wheat "1718" led to greater height, stronger roots, and higher catalase activity than in wild type seedlings. TaLEA2-1 conferred enhanced salt tolerance in transgenic wheat and may be a valuable gene for genetic modification in crops.

Transcriptome analysis of Auricularia fibrillifera fruit-body responses to drought stress and rehydration.

BACKGROUND: Drought stress severely restricts edible fungus production. The genus Auricularia has a rare drought tolerance, a rehydration capability, and is nutrient rich. RESULTS: The key genes and metabolic pathways involved in drought-stress and rehydration were investigated using a transcriptome analysis to clarify the relevant molecular mechanisms. In total, 173.93 Mb clean reads, 26.09 Gb of data bulk, and 52,954 unigenes were obtained. Under drought-stress and rehydration conditions, 14,235 and 8539 differentially expressed genes, respectively, were detected. 'Tyrosine metabolic', 'caffeine metabolism', 'ribosome', 'phagosome', and 'proline and arginine metabolism', as well as 'peroxisome' and 'mitogen-activated protein kinase signaling' pathways, had major roles in A. fibrillifera responses to drought stress. 'Tyrosine' and 'caffeine metabolism' might reveal unknown mechanisms for the antioxidation of A. fibrillifera under drought-stress conditions. During the rehydration process, 'diterpenoid biosynthesis', 'butanoate metabolism', 'C5-branched dibasic acid', and 'aflatoxin biosynthesis' pathways were significantly enriched. Gibberellins and γ-aminobutyric acid were important in the recovery of A. fibrillifera growth after rehydration. Many genes related to antibiotics, vitamins, and other health-related ingredients were found in A. fibrillifera. CONCLUSION: These findings suggested that the candidate genes and metabolites involved in crucial biological pathways might regulate the drought tolerance or rehydration of Auricularia, shedding light on the corresponding mechanisms and providing new potential targets for the breeding and cultivation of drought-tolerant fungi.

Comparative Analysis of Physiological, Enzymatic, and Transcriptomic Responses Revealed Mechanisms of Salt Tolerance and Recovery in Tritipyrum.

Salt stress results in the severe decline of yield and quality in wheat. In the present study, salt-tolerant Tritipyrum ("Y1805") and salt-sensitive wheat "Chinese Spring" ("CS") were selected from 121 wheat germplasms to test their physiological, antioxidant enzyme, and transcriptomic responses and mechanisms against salt stress and recovery. 56 chromosomes were identified in "Y1805" that comprised A, B, and D chromosomes from wheat parent and E chromosomes from Thinopyrum elongatum, adding to salt-tolerant trait. Salt stress had a greater inhibitory effect on roots than on shoots, and "Y1805" demonstrated stronger salt tolerance than "CS." Compared with "CS," the activities of superoxide dismutase and catalase in "Y1805" significantly increased under salt stress. "Y1805" could synthesize more proline and soluble sugars than "CS." Both the net photosynthetic rate and chlorophyll a/b were affected by salt stress, though the level of damage in "Y1805" was significantly less than in "CS." Transcriptome analysis showed that the differences in the transcriptional regulatory networks of "Y1805" were not only in response to salt stress but also in recovery. The functions of many salt-responsive differentially expressed genes were correlated closely with the pathways "peroxisome," "arginine and proline metabolism," "starch and sucrose metabolism," "chlorophyll and porphyrin metabolism," and "photosynthesis."

Integrated transcriptomic and proteomic analysis of Tritipyrum provides insights into the molecular basis of salt tolerance.

BACKGROUND: Soil salinity is a major environmental stress that restricts crop growth and yield. METHODS: Here, crucial proteins and biological pathways were investigated under salt-stress and recovery conditions in Tritipyrum 'Y1805' using the data-independent acquisition proteomics techniques to explore its salt-tolerance mechanism. RESULTS: In total, 44 and 102 differentially expressed proteins (DEPs) were identified in 'Y1805' under salt-stress and recovery conditions, respectively. A proteome-transcriptome-associated analysis revealed that the expression patterns of 13 and 25 DEPs were the same under salt-stress and recovery conditions, respectively. 'Response to stimulus', 'antioxidant activity', 'carbohydrate metabolism', 'amino acid metabolism', 'signal transduction', 'transport and catabolism' and 'biosynthesis of other secondary metabolites' were present under both conditions in 'Y1805'. In addition, 'energy metabolism' and 'lipid metabolism' were recovery-specific pathways, while 'antioxidant activity', and 'molecular function regulator' under salt-stress conditions, and 'virion' and 'virion part' during recovery, were 'Y1805'-specific compared with the salt-sensitive wheat 'Chinese Spring'. 'Y1805' contained eight specific DEPs related to salt-stress responses. The strong salt tolerance of 'Y1805' could be attributed to the strengthened cell walls, reactive oxygen species scavenging, osmoregulation, phytohormone regulation, transient growth arrest, enhanced respiration, transcriptional regulation and error information processing. These data will facilitate an understanding of the molecular mechanisms of salt tolerance and aid in the breeding of salt-tolerant wheat.

Chromosomal Behavior during Meiosis in the Progeny of Triticum timopheevii × Hexaploid Wild Oat.

The meiotic behavior of pollen mother cells (PMCs) of the F2 and F3 progeny from Triticum timopheevii × hexaploid wild oat was investigated by cytological analysis and sequential C-banding-genomic in situ hybridization (GISH) in the present study. A cytological analysis showed that the chromosome numbers of the F2 and F3 progeny ranged from 28 to 41. A large number of univalents, lagging chromosomes, chromosome bridges and micronuclei were found at the metaphase I, anaphase I, anaphase II and tetrad stages in the F2 and F3 progeny. The averages of univalents were 3.50 and 2.73 per cell, and those of lagging chromosomes were 3.37 and 1.87 in the F2 and F3 progeny, respectively. The PMC meiotic indices of the F2 and F3 progeny were 12.22 and 20.34, respectively, indicating considerable genetic instability. A sequential C-banding-GISH analysis revealed that some chromosomes and fragments from the hexaploid wild oat were detected at metaphase I and anaphase I in the progeny, showing that the progeny were of true intergeneric hybrid origin. The alien chromosomes 6A, 7A, 3C and 2D were lost during transmission from F2 to F3. In addition, partial T. timopheevii chromosomes appeared in the form of univalents or lagging chromosomes, which might result from large genome differences between the parents, and the wild oat chromosome introgression interfered with the wheat homologues' normally pairing.