Arabidopsis KLU homologue GmCYP78A72 regulates seed size in soybean

Abstract

Soybean (Glycine max) is one of the most important crops in the world, and its yield is largely determined by grain weight and grain size. However, the genes that regulate soybean seed size have not been identified. CYP78A, which is highly conserved within terrestrial plants, regulates organ development. In Arabidopsis, AtCYP78A5/KLU has been shown to determine seed size. In the present study, soybean CYP78A72 (GmCYP78A72), one of the orthologs of KLU, was over-expressed in both Arabidopsis and soybean to examine its function in plant development. GmCYP78A72 heterologous expression in Arabidopsis resulted in enlarged sepals, petals, seeds and carpel. Over-expression of GmCYP78A72 in soybean resulted in increased pea size, which is an extremely desirable trait for enhancing productivity. Moreover, knock-down of GmCYP78A72 does not reduce grain size. However, silencing of GmCYP78A57, GmCYP78A70 and GmCYP78A72 genes in triplet reduces the seed size significantly indicating functional redundancy of these three GmCYP78A genes. In conclusion, we investigated the role of CYP78A in soybean seed regulation, and our strategy can be effectively used to engineer large seed traits in soybean varieties as well as other crops.

Soybean domestication: the origin, genetic architecture and molecular bases

“…Translational approaches assist with this problem, taking advantage of the wealth of knowledge in the model species and other legumes. For example, soybean homologs of the CYP78A subfamily, which controls organ size and development in Arabidopsis, have been shown to affect seed size in soybean Zhao et al, 2016a). It is also important to note that goals in modern soybean breeding programs have been drastically expanded beyond traditional domestication traits, addressing emerging new diseases and changing environments, optimizing seed protein and oil contents, improving nutritional values and developing specialty traits for specific consumption such as sprouting.…”

Identification of regulatory networks and hub genes controlling soybean seed set and size using RNA sequencing analysis

“…ACC oxidase 1 was significantly enriched in V1 at stage S3-2. Soybean CYP78A72, an ortholog of KLU which positively regulates seed size in soybean (Zhao et al , 2016), was significantly enriched in the cotyledon of V1 but not in V2. Functional categories for the up- or down-regulated DEGs are shown in Tables 8 and 9.…”

“…The Arabidopsis genes KLU , WRKY44 , and STK have been identified genetically as regulators of seed size (Adamski et al , 2009; Garcia et al , 2005; Mizzotti et al , 2012; Zhao et al , 2016). The expression of the soybean homologues of these genes in the RNA-Seq data is shown in Supplementary Fig.…”

Molecular mechanisms underlying stress response and adaptation

“…17,[180][181][182][183] Because of the availability of molecular approaches, Arabidopsis thaliana is an ideal model system to characterize responses to different environmental stresses. [184][185][186][187] When exposed to enhanced UVB radiation, the sad2-1 mutant Arabidopsis thaliana strain accumulates more UV absorption materials and endogenous ABA and activates ROSscavenging enzymes. These physiological changes enhance tolerance to UV.…”