AUTHOR=Ou Siyan , Xu Zhihao , Mai Cuishan , Li Bodi , Wang Jinxiang 

TITLE=Ectopic expression of GmNF-YA8 in Arabidopsis delays flowering via modulating the expression of gibberellic acid biosynthesis- and flowering-related genes and promotes lateral root emergence in low phosphorus conditions

JOURNAL=Frontiers in Plant Science

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2022.1033938

DOI=10.3389/fpls.2022.1033938

ISSN=1664-462X

ABSTRACT=<p>NUCLEAR FACTOR Y subunit alpha (NF-YA), together with NF-YB and NF-YC, regulates plant growth and development, as well as plant responses to biotic and abiotic stresses. Although extensive studies have examined the functions of NF-YAs in <italic>Arabidopsis thaliana</italic>, the roles of NF- YAs in <italic>Glycinme max</italic> are poorly understood. In this study, we identified a phosphorus (P) starvation-responsive <italic>NF-YA8</italic> in soybean. The expression of <italic>GmNF-YA8</italic> is induced by low P or low nitrogen in leaves, but not by potassium or iron starvation, respectively. GmNF-YA8 is localized in the nucleus and plasma membrane. Ectopic expression of <italic>GmNF-YA8</italic> inhibits plant growth and delayed flowering in <italic>Arabidopsis</italic>. Exogenous application of gibberellic acid (GA) rescues the delayed flowering phenotype in <italic>Arabidopsis</italic> overexpressing <italic>GmNF-YA8</italic> lines GmNF-YA8OE-05 and GmNF-YA8OE-20. Moreover, quantitative real time PCR (qRT-PCR) verified that overexpression of <italic>GmNF-YA8</italic> downregulates <italic>GA20ox2</italic> and <italic>GA3ox2</italic> expression, but upregulates <italic>GA2ox2</italic> and <italic>GA2ox3</italic> that encode enzymes, which inactive bioactive GAs. Consistent with the late flowering phenotype of <italic>Arabidopsis</italic> trangenic lines that overexpress <italic>GmNF-YA8</italic>, the transcript levels of flowering-promoting genes <italic>AP1</italic>, <italic>CO</italic>, <italic>LFY</italic>, and <italic>SOC1</italic> are reduced. In addition, overexpression of <italic>GmNF-YA8</italic> promotes the emergence of lateral root (LR) primordium from epidermis rather than the initiation of LR in low P, and increases the LR density in low nitrogen. Our results provide insights into the roles of <italic>GmNF-YA8</italic>.</p>