The brassinosteroid biosynthesis gene TaD11-2A controls grain size and its elite haplotype improves wheat grain yields

Seo

et al. 2023

Plants

Rice is a major crop, providing calories and food for most of the world’s population. Currently, the global population is rapidly increasing, and securing a yield of rice that can satisfy everyone is an ongoing challenge. The yield of rice can be increased by controlling 1000-grain weight as one of the important determining factors. Grain length, grain width, grain thickness, and 1000-grain weight, which determine grain size, are controlled by QTLs. To identify QTLs related to grain size, we screened and then mapped 88 RIL individuals derived from a cross between JJ625LG, which has a long grain size, long spindle-shaped grains, and low 1000-grain weight, and Namchan, which has short grains with round shape and heavy 1000-grain weight. In 2021 and 2022, 511 SNP markers were used to map QTLs related to grain size to a physical map. The QTLs found to be related to grain size are evenly distributed on chromosomes 2, 3, 5, 10, and 11. The mapping results also show that the QTLs qGl3-2, qRlw3, and qRlw3-2 of chromosome 3, and qGt5 and qRlw5 of chromosome 5 are, respectively, associated with GS3 and qSW5, which are the major genes previously cloned and found to be related to grain size. In addition, qGw10 and qGw10-1, which were additionally detected in this study, were found to be associated with Os10g0525200 (OsCPq10), a potential candidate gene involved in controlling grain size. This gene codes for a cytochrome P450 family protein and is reported to have a positive effect on grain size by interacting with proteins related to mechanisms determining grain size. In particular, OsCPq10 was screened in the same identified QTL region for 2 consecutive years, which is expected to have a positive effect on grain size. These results will be helpful for breeding elite rice cultivars with high yields through additional fine mapping related to grain size.

Section: Discussionmentioning

confidence: 99%

Identification of Potential QTLs Related to Grain Size in Rice

Seo

et al. 2023

Plants

“…Transferring the gene encoding C-22 hydroxylase, an enzyme involved in sterol biosynthesis, into rice significantly increased the BR hormone content and the TKW, and the increase in TKW resulted from BR stimulating the transport of photosynthates in rice ( Wu et al., 2008 ). Knockout of TaD11-2A results in dwarfism, a significant decrease in endogenous BR content, and smaller grains in wheat ( Xu et al., 2022 ). TaBRI1 is the BR receptor gene in wheat, and TaBRI1 knockout mutants were insensitive to exogenous BR and significantly reduced TKW ( Fang et al., 2020 ).…”

Section: Discussionmentioning

confidence: 99%

Identification of candidate gene for the defective kernel phenotype using bulked segregant RNA and exome capture sequencing methods in wheat

et al. 2023

Wheat is a significant source of protein and starch worldwide. The defective kernel (Dek) mutant AK-3537, displaying a large hollow area in the endosperm and shrunken grain, was obtained through ethyl methane sulfonate (EMS) treatment of the wheat cultivar Aikang 58 (AK58). The mode of inheritance of the AK-3537 grain Dek phenotype was determined to be recessive with a specific statistical significance level. We used bulked segregant RNA-seq (BSR-seq), BSA-based exome capture sequencing (BSE-seq), and the ΔSNP-index algorithm to identify candidate regions for the grain Dek phenotype. Two major candidate regions, DCR1 (Dek candidate region 1) and DCR2, were identified on chromosome 7A between 279.98 and 287.93 Mb and 565.34 and 568.59 Mb, respectively. Based on transcriptome analysis and previous reports, we designed KASP genotyping assays based on SNP variations in the candidate regions and speculated that the candidate gene is TraesCS7A03G0625900 (HMGS-7A), which encodes a 3-hydroxy-3-methylglutaryl-CoA synthase. One SNP variation located at position 1,049 in the coding sequence (G>A) causes an amino acid change from Gly to Asp. The research suggests that functional changes in HMGS-7A may affect the expression of key enzyme genes involved in wheat starch syntheses, such as GBSSII and SSIIIa.

“…Saline treatments using a 125 mM NaHCO 3 : Na 2 CO 3 solution at a molar ratio of 5:1 (Sigma-Aldrich, Shanghai, China) were conducted for 5 days (Zhang et al, 2023). Drought-stress treatments using a 30% polyethylene glycol (PEG) 6000 solution (Sigma-Aldrich) were conducted for 3 days (Xu et al, 2022). CDC was assessed using the following formula: Drought coe cient of plant height/root length/SPAD(DC PH/RL/SPAD ) = (PEG stress treatment plant height/root length/SPAD measurements -control group measurements) × 100%, CDC = (DC PH + DC RL + DC SPAD )/3.…”

Section: Plant Materials and Growth Conditionsmentioning

confidence: 99%

“…To determine TaCHLI haplotype selection characteristics in wheat breeding, we assessed 200 Chinese wheat accessions from different breeding years (Xu et al, 2022) and used them to analyze frequency variations in different TaCHLI-7A/B haplotypes. TaCHLI-7B-HapII frequency was raised from landraces (%) to modern cultivars (%) (Fig.…”

Section: Tachli Haplotype Analysismentioning

confidence: 99%

A highly conserved amino acid mutation in TaCHLI-7D affects leaf color and yield-related traits in wheat

Wang,

Xu,

Wang

et al. 2024

Preprint

Self Cite

Chlorophyll is essential for plant growth and productivity. The CHLI subunit of the magnesium chelatase protein plays a key role inserting magnesium into protoporphyrin IX during chlorophyll biosynthesis. Here, we identify a novel wheat mutant chlorophyll (chl) that exhibits yellow-green leaves, reduced chlorophyll levels, and increased carotenoid content, leading to an overall decline in yield-related traits. Map-based cloning reveals that the chl phenotype is caused by a point mutation (Asp186Asn) in the TaCHLI-7D gene, which encodes subunit I of magnesium chelatase. Furthermore, the three TaCHLI mutants: chl-7b-1 (Pro82Ser), chl-7b-2 (Ala291Thr), and chl-7d-1 (Gly357Glu), also showed significant reductions in chlorophyll content and yield-related traits. However, TaCHLI-7D overexpression in rice significantly decreased thousand-grain weight, yield per plant, and germination. Additionally, natural variations in TaCHLI-7A/B are significantly associated with flag leaf, spike-stem length, and yield per plant. Notably, the favorable haplotype, TaCHLI-7B-HapII, which displayed higher thousand-grain weight and yield per plant, is positively selected in wheat breeding. Our study provides insights on the regulatory molecular mechanisms underpinning leaf color and chlorophyll biosynthesis, and highlights TaCHLI functions, which provide useful molecular markers and genetic resources for wheat breeding.