Auxin has been reported to regulate plant growth and development, as well as to mediate plant adaption to abiotic stresses, including drought. AUX/LAX family displays auxin uptake functions and comprises four highly conserved genes AUX1 and LIKE AUX1 (LAX1, LAX2, and LAX3) in Arabidopsis. There are fifteen GmLAX family genes in the soybean genomes and several members were regulated by dehydration stress. In this study, the sequence differences and expression pattern of GmLAXs-I were analyzed under stress treatment between the soybean drought-tolerant Jindou 21 and drought-sensitive varieties Zhongdou 33. Five homologous genes of AUX1 were all responsive to PEG, salt, ABA and IAA stimuli. There were two SNPs in the promoter region of GmLAX4 gene, and this gene was differentially expressed in two cultivars. Moreover, our results showed YFP-GmLAXs are predominantly localized in plasma membrane. Taken together, our results suggest that GmLAXs are involved in abiotic response, which can provide theoretical and technical support for the genetic improvement of soybean drought tolerance.
Red coleoptiles can help crops to cope with adversity and the key genes that are responsible for this trait have previously been isolated from Triticum aestivum, Triticum urartu, and Aegilops tauschii. This report describes the use of transcriptome analysis to determine the candidate gene that controls the trait for white coleoptiles in T. monococcum by screening three cultivars with white coleoptiles and two with red coleoptiles. Fifteen structural genes and two transcription factors that are involved in anthocyanin biosynthesis were identified from the assembled UniGene database through BLAST analysis and their transcript levels were then compared in white and red coleoptiles. The majority of the structural genes reflected lower transcript levels in the white than in the red coleoptiles, which implied that transcription factors related to anthocyanin biosynthesis could be candidate genes. The transcript levels of MYC transcription factor TmMYC-A1 were not significantly different between the white and red coleoptiles and all of the TmMYC-A1s contained complete functional domains. The deduced amino acid sequence of the MYB transcription factor TmMYB-A1 in red coleoptiles was homologous to TuMYB-A1, TaMYB-A1, TaMYB-B1, and TaMYB-D1, which control coleoptile color in corresponding species and contained the complete R2R3 MYB domain and the transactivation domain. TmMYB-a1 lost its two functional domains in white coleoptiles due to a single nucleotide deletion that caused premature termination at 13 bp after the initiation codon. Therefore, TmMYB-A1 is likely to be the candidate gene for the control of the red coleoptile trait, and its loss-of-function mutation leads to the white phenotype in T. monococcum.
Leaf-chewing insects are important pests that cause yield loss and reduce seed quality in soybeans (Glycine max). Breeding soybean varieties that are resistant to leaf-chewing insects can minimize the need for insecticide use and reduce yield loss. The marker gene for QTL-M, Glyma.07g110300 (LOC100775351) that encodes a UDP-glycosyltransferase (UGT) is the major determinant of resistance against leaf-chewing insects in soybean; it exhibits a loss of function in insect-resistant soybean germplasms. In this study, Agrobacterium-mediated transformation introduced the CRISPR/Cas9 expression vector into the soybean cultivar Tianlong No. 1 to generate Glyma.07g110300-gene mutants. We obtained two novel types of mutations, a 33-bp deletion and a single-bp insertion in the GmUGT coding region, which resulted in an enhanced resistance to Helicoverpa armigera and Spodoptera litura. Additionally, overexpressing GmUGT produced soybean varieties that were more sensitive to H. armigera and S. litura. Both mutant and overexpressing lines exhibited no obvious phenotypic changes. The difference in metabolites and gene expression suggested that GmUGT is involved in imparting resistance to leaf-chewing insects by altering the flavonoid content and expression patterns of genes related to flavonoid biosynthesis and defense. Furthermore, ectopic expression of the GmUGT gene in the ugt72b1 mutant of Arabidopsis substantially rescued the phenotype of H. armigera resistance in the atugt72b1 mutant. Our study presents a strategy for increasing resistance against leaf-chewing insects in soybean through CRISPR/Cas9-mediated targeted mutagenesis of the UGT genes.
The development of a salt-tolerant hexaploid triticale cultivar offers an economical and efficient solution for utilizing marginal land. Understanding how hexaploid triticales respond to salt stress is essential if this goal is to be achieved. A genome-wide association study (GWAS), along with transcriptome and proteome analyses, were used in the present study to determine the molecular responses to salt stress in hexaploid triticale. In total, 81 marker-trait associations for 10 salt-tolerance traits were identified in 153 hexaploid triticale accessions, explaining 0.71% to 56.98% of the phenotypic variation, and 54 GWAS-associated genes were uncovered. A total of 67, 88, and 688 differential expression genes were co-expressed at both the transcriptomic and proteomic levels after 4, 12, and 18 h of salt stress, respectively. Among these differentially expressed genes, six appeared in the coincident expression trends for both the transcriptomic and proteomic levels at the seed germination stage. A total of nine common KEGG pathways were enriched at both the transcriptomic and proteomic levels at 4, 12, and 18 h. After integrating GWAS-target genes with transcriptomics and proteomics approaches that the candidate gene late embryogenesis abundant protein 14 ( LEA14 ) was up-regulated at the transcriptomic and proteomic levels. LEA14 contained important stress-responsive cis-acting regulatory elements that could be dynamically regulated by the binding of transcription factors (TFs). This suggested that LEA14 was a key gene associated with salt tolerance in hexaploid triticale and could respond quickly to salt stress. This study improved understanding about the potential molecular mechanisms associated with hexaploid triticale salt tolerance and contributed to the breeding of salt-tolerant germplasms and the utilization of saline soils.
The awnless trait is the favorite trait for wheat breeding in Qinghai, China, but the major gene underlying the trait is unknown. This study aimed to analyze a recombinant inbred line (RIL) population containing 112 lines by crossing common wheat varieties GY448 (awnless) and GY115 (awned) using genotyping-by-sequencing analysis. A total of 56.62 Gb of clean sequence data were generated. A major gene was identified for the awnless trait based on 101,275 single-nucleotide polymorphisms by quantitative trait locus (QTL)-seq analysis. The region from 685.50 to 709.77 Mb on chromosome 5AL contained 334 genes and 394 transcripts, including B1, the major gene controlling the awnless trait. A 25-bp indel located in the B1 promoter region has a diagnostic value for the awnless/awned genotypes in the RIL population. A total of 42 spring wheat cultivars in Qinghai, China, were analyzed. Further, 23 awnless cultivars had the alleles of the GY448 parent, while 19 awned cultivars had the alleles of the GY115 parent. B1 is crucial in the awnless trait in wheat cultivars in Qinghai, China. The findings of this study might guide the breeding of new wheat cultivars in this region.
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