Overexpression of OsSPL14 results in transcriptome and physiology changes in indica rice ‘MH86’

Abstract

Oryza sativa SPL14 (OsSPL14), identified as the IDEAL PLANT ARCHITECTURE1 or WEALTHY FARMER'S PANICLE gene, plays a critical role in regulating rice plant architecture. Here, OsSPL14-overexpression transgenic rice plants had shorter growth periods, short narrow flag leaves, and thick green leaves compared with wild type 'MH86' plants (WT). Additionally, transgenic lines had higher chlorophyll a (Chl a), chlorophyll b (Chl b), and carotenoid (Car x) contents at both seedling and mature stages. Expression of OsSPL14 increased at transcriptional level, and OsSPL14 protein level was substantially increased in transgenic lines relative to WT. A transcriptome analysis identified 473 up-regulated and 103 downregulated genes in the transgenic plants. The expression of differentially expressed genes (DEGs) involved in carotenoid biosynthesis, abscisic acid (ABA) metabolism, and lignin biosynthesis increased significantly. Most of DEGs participated in "plant hormone signal transduction" and "starch and sucrose metabolism" were also up-regulated in the transgenic plants. In addition, there were higher ABA and gibberellin acid 3 (GA 3 ) levels in OsSPL14-overexpression rice plants at seedling and tillering stages compared with WT. In contrast with that of WT, lignin and cellulose contents of culm increased distinctly. Also, silicon and potassium contents increased dramatically in transgenic lines. Meanwhile, the chalkiness ratios and chalkiness degrees decreased, and the gel consistency levels improved in transgenic lines. Thus, overexpression of OsSPL14 influenced growth period, leaf development, hormonal levels, culm composition, and grain quality characters of rice, which provides more insight into the function of OsSPL14.

IPA1 improves drought tolerance by activating SNAC1 in rice

“…The mature IPA1 -Cas9 plants demonstrated dwarfism and more tillers, shorter and narrower flag leaves, and shorter panicles compared with WT plants. Previous studies have shown that overexpression of IPA1 decreases tiller number and yields a strong stalk [ 41 , 42 ]. IPA1 is most highly expressed in the roots of seedlings, and knocking down IPA1 may affect root development and thus decrease the soil water uptake capacity and tolerance to drought stress.…”

Diversity of Panicle Architecture and Traits Influencing Grain Filling

“…The regulatory role of IPA1 is antagonistic to that of IPI1, where IPI1 controls tiller number and panicle size by modulating IPA1 protein levels in a tissue-specific manner . Additionally, OsSPL14-overexpression transgenic rice plants confers higher ABA and gibberellin acid 3 (GA3) levels at seedling and tillering stages (Lian et al 2020). Hashida et al (2013) suggested that a gene encoding sucrose phosphate synthase OsSPS1 introduced into japonica rice Koshihikari from indica rice Kasalath improved spikelet number by 38-47% in transgenic rice because the higher activity of the enzyme increased sucrose synthesis of source leaf and improved partitioning of dry matter for panicle growth that increased secondary branch number.…”