GW5‐Like, a homolog of GW5, negatively regulates grain width, weight and salt resistance in rice

Abstract

Grain size is an important determinant of yield potential in crops. We previously demonstrated that natural mutations in the regulatory sequences of qSW5/GW5 confer grain width diversity in rice. However, the biological function of a GW5 homolog, named GW5‐Like (GW5L), remains unknown. In this study, we report on GW5L knockout mutants in Kitaake, a japonica cultivar (cv.) considered to have a weak gw5 variant allele that confers shorter and wider grains. GW5L is evenly expressed in various tissues, and its protein product is localized to the plasma membrane. Biochemical assays verified that GW5L functions in a similar fashion to GW5. It positively regulates brassinosteroid (BR) signaling through repression of the phosphorylation activity of GSK2. Genetic data show that GW5L overexpression in either Kitaake or a GW5 knockout line, Kasaorf3 (indica cv. Kasalath background), causes more slender, longer grains relative to the wild‐type. We also show that GW5L could confer salt stress resistance through an association with calmodulin protein OsCaM1‐1. These findings identify GW5L as a negative regulator of both grain size and salt stress tolerance, and provide a potential target for breeders to improve grain yield and salt stress resistance in rice.

Exploring the Brassinosteroid Signaling in Monocots Reveals Novel Components of the Pathway and Implications for Plant Breeding

“…Subcellular localization, biochemical function and positive role of the GW5L protein in the BR signaling regulation are similar to those of the domestication-related GW5 homolog [88]. Moreover, the GW5 and GW5L proteins may also be involved in the salt-stress reaction through interaction with the calmodulin protein OsCaM1-1 which is a positive regulator of the salt stress tolerance [88,89]. It was suggested that GW5 and GW5L may directly or indirectly repress transcription of the OsCaM1-1 gene.…”

“…Therefore, both GW5 and GW5L may act as regulators of grain size and the salt-stress tolerance in rice (Figure 1). It was suggested that the GW5 and GW5L homologs may serve as candidates for genetic manipulation through targeted genome editing to improve grain yield and salt-stress tolerance in rice and perhaps in other cereals [44,88].…”

Rice microtubule‐associated protein IQ67‐DOMAIN14 regulates grain shape by modulating microtubule cytoskeleton dynamics

“…While these functions are diverse, no coherent mechanistic framework has emerged for the cellular basis underlying the altered morphology. Importantly, although GW5 and GW5 like (GW5L, Tian et al , ) share similarities with OsIQD14 regarding sequence and control of seed shape, both GW5 and GW5L are plasma membrane‐localized protein involving in brassinosteroid signalling by regulating BIN2 activity. In contrast, we identified OsIQD14 as a key regulator of grain shape by acting on cell shape determination through controlling the MT cytoskeleton, making this a novel target for breeding approaches.…”

Genetic dissection of heterosis of indica–japonica by introgression line, recombinant inbred line and their testcross populations

“…A few already reported genes in rice were co-located with the heterotic QTLs identified in this study such as qGYP10.1 ( OsPQT3 , increases grain yield in the field) 49 , qPN9.2 and qTGW9 ( OsCCC1 for cell elongation and panicle number 50 , OsTb2 for tillering and grain yield per panicle 51 , and Oshox4 affecting bushy tillers 52 , OsZHD1 for tiller number 53 , and OsEATB , ERF protein associated with tillering and panicle branching 54 , qTGW1.1 ( GW5L , negatively regulates grain width and weight) 55 , qTGW2.2 ( OsGS1 , growth rate and grain filling) 56 , qTGW3.3 ( GS3 , grain length and weight) 57 , qTGW3.6 ( OsMADS34 , grain size and yield 58 , Pho1 , the size of mature seeds and the starch content) 59 , and qTGW6.1 ( OsKASI , 1000-grain weight and tiller number) 60 . All the above mentioned genes provided heterotic effects with heterozygous alleles in UD-type or D-type M-QTLs.…”