Abstract
ABSTRACT: YUCCA (YUC) proteins have critical roles in plant growth and development through their involvement in auxin production. Rice (Oryza sativa L. cv Nipponbare) has 14 OsYUC proteins, but little is known regarding their functional redundancy. In this study, transgenic rice seedlings expressing GUS-tagged antisense-OsYUC2 under the control of the ubiquitin promoter were used to investigate the effects of OsYUC2 deficiency on seedling growth and development. GUS staining showed that antisense-OsYUC2 was expressed primarily in rapidly dividing cells in callus, vegetative, and reproductive tissues. Phenotypic analysis showed that callus differentiation was compromised in OsYUC2 antisense rice. Adverse vegetative effects were observed in shoot height and embryonic, adventitious, and lateral root numbers. Reproductive tissues were also impacted, with reductions in panicle length, flower number, seed setting number, seed setting rate, and grain weight. Auxin analysis showed that indole-3-acetic acid (IAA) levels were reduced in OsYUC2 antisense rice, and exogenous addition of 3-indolebutyric acid (IBA, an analogue of IAA) partially rescued defective growth phenotypes. Taken together, these results indicated that deficiency of OsYUC2 impairs auxin biosynthesis, thereby affecting rice growth and development.
Highlights
Auxin plays critical roles in plant growth and development and is involved in responses to abiotic and biotic stresses (Feraru et al, 2019; Yao et al, 2018a; Yao et al, 2018b; Zhang et al, 2018; Zhao, 2018)
Auxin analysis showed that indole-3-acetic acid (IAA) levels were reduced in OsYUC2 antisense rice, and exogenous addition of 3-indolebutyric acid (IBA, an analogue of IAA) partially rescued defective growth phenotypes
These results indicated that deficiency of OsYUC2 impairs auxin biosynthesis, thereby affecting rice growth and development
Summary
Auxin plays critical roles in plant growth and development and is involved in responses to abiotic and biotic stresses (Feraru et al, 2019; Yao et al, 2018a; Yao et al, 2018b; Zhang et al, 2018; Zhao, 2018). The regulatory roles of auxin are achieved through the activity of several proteins, including YUCCA (YUC) proteins, which are involved in auxin biosynthesis; PIN proteins, which are involved in auxin transport; and ARF receptors, which participate in auxin perception (Tognetti et al, 2012). Disruption of these processes affects auxin function and leads to impairment in plant growth and development (Inahashi et al, 2018; Muller-Moule et al, 2016; Yamamoto et al, 2007; Yao et al, 2018b). Tryptophan-dependent biosynthesis, which is thought to be the predominant route for plant IAA production, uses tryptophan as the main IAA precursor (Olatunji et al, 2017). In the TAA/YUC pathway, TAA aminotransferases convert tryptophan to IPA, which is further converted to IAA by YUC family monooxygenases (Olatunji et al, 2017)
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