Leaf angle is an important agronomic trait that determines p...

created [InstanceEdit:9828981] Naithani, Sushma, 2023-02-20
dbId 9828934
displayName Leaf angle is an important agronomic trait that determines p...
literatureReference
schemaClass Summation
text Leaf angle is an important agronomic trait that determines plant architecture, photosynthetic efficiency, and crop yield. Erect leaves are suitable for rice dense planting, reducing mutual shading between plants to increase photosynthetic efficiency and crop yield. Leaf angle is determined by the development of lamina joint; asymmetric cell division and elongation on the adaxial or abaxial sides of lamina joint cause leaf angle changes (Feng et al., 2016). Phytohormones play essential roles in regulating the lamina joint development and leaf angle (Luo et al., 2016; Wang et al., 2018). Brassinosteroid (BR) regulate the asymmetric elongation of adaxial cells of the lamina joint to favour increase in rice leaf angle (Tong et al., 2014). Overexpression of BR biosynthesis genes or signaling components resulted in large leaf angle. On the other hand cytokinin signaling results in the formation of smaller leaf angle. Hormone strigolactones (SL) inhibits leaf angle by interfering with the BR signaling pathway. Thus, SL and BR signaling pathways antagonistically control rice tillering/leaf angle. Cytokinins also inhibit the leaf angle and cytokinin signaling is regulated in the lemma joints by promoting its degradation. Cytokinins OXIDASE/DEHYDROGENASE (OsCKX3) is highly expressed in lamina joint, and the encodes an endoplasmic reticulum localized enzyme OsCKX3 (Huang et al., 2023). It preferentially catabolizes trans-zeatin and isopentenyladenine that leads to depletion of the cytokinins level. The reduction in cytokinin levels results in larger leaf angles. In the osckx3 knockout mutants, levels of cytokinins in lamina joint remain high resulting in smaller leaf angles. In contrast, OsCKX3 overexpressing transgenic plants have larger leaf angles. Also, osckx3 mutants have increase in primary branches, grain size, and leaf size. Thus, OsCKX3 is negative regulator of leaf angle by mediating the cytokinins degradation in lamina joint (Huang et al., 2023).