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Salt stress is an abiotic stress factor that limits high yields, and thus identifying salt tolerance genes is very important for improving the tolerance of salt in wheat. In this study we identified 274 TaRING-H2 family members and analyzed their gene positions, gene structures, conserved structural domains, promoter cis-acting elements and covariance relationships. And we investigated TaRING-H2-120 (TaSDIR1) in salt stress. Transgenic lines exhibited higher salt tolerance in the germination and seedling stages. Compared with the wild type, overexpression of TaSDIR1 upregulated the expression of genes encoding enzymes related to the control of reactive oxygen species (ROS), thereby reducing the accumulation of ROS, as well as increased the expression of ion transport-related genes to limit the inward flow of Na+ in vivo and maintain a higher K+/Na+ ratio. The expression levels of these genes were opposite in lines where TaSDIR1 was silenced by BSMV-VIGS, and the silenced wheat exhibited higher salt sensitivity. Arabidopsis mutants and heterologous TaSDIR1 overexpressing lines had similar salt stress tolerance phenotypes. We also demonstrated that TaSDIR1 interacted with TaSDIR1P2 in vivo and in vitro. A sequence of 80–100 amino acids in TaSDIR1P2 encoded a coiled coil domain that was important for the activity of E3 ubiquitin ligase, and it was also the core region for the interaction between TaSDIR1 and TaSDIR1P2. Overall, our results suggest that TaSDIR1 positively regulates salt stress tolerance in wheat. [ABSTRACT FROM AUTHOR]

The discovery and identification of gene families by using wide-genome and public databases is an effective way to gain initial insight into gene function, which also is one of the current hot spots of research. Chlorophyll ab-binding proteins (LHC) are important for photosynthesis and widely involved in plant adversity stress. However, the study in wheat has not been reported. In this study, we identified 127 TaLHC members from common wheat which were unevenly distributed on all chromosomes except 3B and 3D. All members divided into three subfamilies, LHC a, LHC b and the LHC t which was only discovered in wheat. All of them had maximum expression in leaves and contained multiple light-responsive cis-acting element, which were evidence of the extensive involvement of LHC families in photosynthesis. In addition, we also analyzed their collinear relationship, targeting relationship with miRNA and their responses under different stresses. Based on these analyses, it was found that TaLHC86 was an excellent candidate gene for stress resistance. The full-length ORF of TaLHC86 was 792 bp and was localized on the chloroplasts. The salt tolerance of wheat was reduced when BSMV-VIGS silenced TaLHC86 , and the photosynthetic rate and electron transport were also seriously affected. This study made a comprehensive analysis of the TaLHC family and found that TaLHC86 was a good gene for salt tolerance. [ABSTRACT FROM AUTHOR]

The discovery and identification of gene families by using wide-genome and public databases is an effective way to gain initial insight into gene function, which also is one of the current hot spots of research. Chlorophyll ab-binding proteins (LHC) are important for photosynthesis and widely involved in plant adversity stress. However, the study in wheat has not been reported. In this study, we identified 127 TaLHC members from common wheat which were unevenly distributed on all chromosomes except 3B and 3D. All members divided into three subfamilies, LHC a, LHC b and the LHC t which was only discovered in wheat. All of them had maximum expression in leaves and contained multiple light-responsive cis-acting element, which were evidence of the extensive involvement of LHC families in photosynthesis. In addition, we also analyzed their collinear relationship, targeting relationship with miRNA and their responses under different stresses. Based on these analyses, it was found that TaLHC86 was an excellent candidate gene for stress resistance. The full-length ORF of TaLHC86 was 792 bp and was localized on the chloroplasts. The salt tolerance of wheat was reduced when BSMV-VIGS silenced TaLHC86 , and the photosynthetic rate and electron transport were also seriously affected. This study made a comprehensive analysis of the TaLHC family and found that TaLHC86 was a good gene for salt tolerance. [ABSTRACT FROM AUTHOR]

Summary: Drought is a deleterious abiotic stress factor that constrains crop growth and development. Post‐translational modification of proteins mediated by the ubiquitin–proteasome system is an effective strategy for directing plant responses to stress, but the regulatory mechanisms in wheat remain unclear. In this study, we showed that TaSDIR1‐4A is a positive modulator of the drought response. Overexpression of TaSDIR1‐4A increased the hypersensitivity of stomata, root length and endogenous abscisic acid (ABA) content under drought conditions. TaSDIR1‐4A encodes a C3H2C3‐type RING finger protein with E3 ligase activity. Amino acid mutation in its conserved domain led to loss of activity and altered the subcellular localization. The membrane‐bound transcription factor TaWRKY29 was identified by yeast two‐hybrid screening, and it was confirmed as interacting with TaSDIR1‐4A both in vivo and in vitro. TaSDIR1‐4A mediated the polyubiquitination and proteolysis of the C‐terminal amino acid of TaWRKY29, and its translocation from the plasma membrane to the nucleus. Activated TaWRKY29 bound to the TaABI5 promoter to stimulate its expression, thereby positively regulating the ABA signalling pathway and drought response. Our findings demonstrate the positive role of TaSDIR1‐4A in drought tolerance and provide new insights into the involvement of UPS in the wheat stress response. [ABSTRACT FROM AUTHOR]

Ethylene has an important role in regulating plant growth and development as well as responding to adversity stresses. The 1-aminocyclopropane-1-carboxylate synthase (ACS) is the rate-limiting enzyme for ethylene biosynthesis. However, the role of the ACS gene family in wheat has not been examined. In this study, we identified 12 ACS members in wheat. According to their position on the chromosome, we named them TaACS1-TaACS12, which were divided into four subfamilies, and members of the same subfamilies had similar gene structures and protein-conserved motifs. Evolutionary analysis showed that fragment replication was the main reason for the expansion of the TaACS gene family. The spatiotemporal expression specificity showed that most of the members had the highest expression in roots, and all ACS genes contained W box elements that were related to root development, which suggested that the ACS gene family might play an important role in root development. The results of the gene expression profile analysis under stress showed that ACS members could respond to a variety of stresses. Protein interaction prediction showed that there were four types of proteins that could interact with TaACS. We also obtained the targeting relationship between TaACS family members and miRNA. These results provided valuable information for determining the function of the wheat ACS gene, especially under stress. [ABSTRACT FROM AUTHOR]

Drought negatively affects plant growth and development to cause major yield losses in crops. Transcription factors (TFs) play important roles in abiotic stress response signaling in plant. However, the biological functions of membrane-bound transcription factors (MTFs) in abiotic stress have rarely been studied in wheat. In this study, we identified a homologue of the maize ZmNTL1 gene in wheat, which was designated as TaNTL1. TaNTL1 is a NAC family MTF (NTM1-like, NTL proteins) encoding 481 amino acid residues with a transmembrane motif at the C-terminal. Quantitative results and expression profile analysis showed that TaNTL1 could respond to drought. We demonstrated the transcriptional activity of TaNTL1 and that it could specifically bind to NAC recognition cis-acting elements (NACBS). The full-length TaNTL1 protein localized in the plasma membrane and TaNTL1 lacking the transmembrane motif (TaNTL1-ΔTM) localized in the nucleus. TaNTL1 was proteolytically activated by PEG6000 and abscisic acid (ABA). Phenotypic and physiological analyses showed that overexpression transgenic Arabidopsis exhibited enhanced drought resistance, which was greater with TaNTL1-ΔTM than TaNTL1. Transient silencing of TaNTL1 significantly reduced the resistance to drought stress in wheat. Germination by the TaNTL1 and TaNTL1-ΔTM transgenic Arabidopsis seeds was also hypersensitive to ABA. Most of the stress-related genes in transgenic plants were upregulated under drought conditions. These results suggest that MTF TaNTL1 is a positive regulator of drought and it may function by entering the nucleus through cleavage. • TaNTL1 identified as a NAC family membrane-bound transcription factor in wheat. • C-terminal transmembrane domain of TaNTL1 determines its subcellular localization. • TaNTL1 has a positive regulatory role under drought stress conditions. [ABSTRACT FROM AUTHOR]

Drought stress is an important factor that affects crop yields and quality. E3 ubiquitin ligase has crucial roles in the responses to abiotic stresses. However, few studies have investigated the role of E3 ubiquitin ligase during drought stress in wheat. In this study, we cloned and identified the orthologous gene of Oryza sativa Salt-, ABA- and Drought-Induced RING Finger Protein 1 (OsSADR1) in wheat (Triticum aestivum L.) called TaSADR1. TaSADR1 encodes a protein containing 486 amino acids with a C3HC4 type RING finger conserved domain at the N-terminal. We confirmed that TaSADR1 has an E3 ubiquitin ligase activity and it is located in the nucleus. High expression of TaSADR1 was induced by treatment with PEG6000 and abscisic acid (ABA). TaSADR1 -overexpressing transgenic Arabidopsis plants exhibited decreased drought tolerance. Under drought stress, compared with the wild-type (WT) lines, TaSADR1 -overexpressing transgenic Arabidopsis lines had lower proline and chlorophyll contents, and antioxidant enzyme activities (superoxide dismutase, peroxidase, and catalase), whereas the water loss rate, malondialdehyde content, and relative electrolyte leakage were higher. In addition, the overexpressing transgenic Arabidopsis lines were more sensitive to mannitol and ABA treatment at seed germination and during seedling growth. The expression levels of genes related to stress were downregulated under drought conditions in the transgenic plants. Our results demonstrate that TaSADR1 may negatively regulate drought stress responses by regulating the expression of stress-related genes. • TaSADR1 in wheat identified as a C3HC4 type RING E3 ubiquitin ligase. • TaSADR1 possesses E3 ligase activity. • TaSADR1 has a negative role in drought resistance. [ABSTRACT FROM AUTHOR]

TaGW2 has been identified as a key determinant of the grain weight in wheat (Triticum aestivum L.). In our previous study, we found that the grain size differs in Chinese Spring (CS) and its TaGW2-6A allelic variant (NIL31). In addition, the expression of the key starch biosynthesis enzyme gene TaAGPS differs significantly in the two materials. However, the underlying molecular mechanism associated with the action of TaGW2-6A has not been reported. In the present study, we found that TaGW2-6A-CS interacted with TaAGPS, whereas TaGW2-6A-NIL31 did not interact with it in vitro and in vivo. Furthermore, we found that the C-terminal LXLX domain (376–424 aa) of TaGW2-6A recognized TaAGPS. However, the TaGW2-6A allelic variant lacked this key interaction region due to premature translation termination. We also found that TaGW2-6A-CS can ubiquitinate TaAGPS and degrade it via the 26 S proteasome pathway. In addition, our analysis of the activity of ADP-glucose pyrophosphorylase (AGPase) indicated that the AGPase level in the endosperm cells was lower in CS than NIL31. Cytological observations demonstrated that the average number of starch granules and the average area of starch granules in endosperm cells were lower in CS than NIL31. The overexpression of TaAGPS positively regulated the seed size in transgenic Arabidopsis. Our findings provide novel insights into the molecular mechanism that allows TaGW2-6A - TaAGPS to regulate seed size via the starch synthesis pathway. • Wheat TaGW2-6A interacted with TaAGPS in vitro and in vivo. • TaGW2-6A ubiquitinated and degraded TaAGPS via the 26S proteasome pathway. • ADP-glucose pyrophosphorylase activity and cytological observations differed in endosperm cells of CS and NIL31. [ABSTRACT FROM AUTHOR]