AUTHOR=Xu Peipei , Cai Weiming 

TITLE=Function of Brassica napus BnABI3 in Arabidopsis gs1, an Allele of AtABI3, in Seed Development and Stress Response

JOURNAL=Frontiers in Plant Science

VOLUME=10

YEAR=2019

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2019.00067

DOI=10.3389/fpls.2019.00067

ISSN=1664-462X

ABSTRACT=<p>Abscisic acid (ABA) has been implicated in plant adaptation to various environmental stresses in addition to the regulation of seed dormancy and leaf senescence. ABI3 is a B3 domain-containing family protein and functions in the ABA signaling pathway during seed development. To date, the ABI3 orthologous have not been studied in <italic>Brassica napus</italic>. The aim of this study is to investigate the function of <italic>BnABI3</italic> in plant development and stress response. Here, we identified an <italic>Arabidopsis</italic> line (<italic>gs1</italic>) from a population of mutagenized seeds and showed that GS1 is a new allele of <italic>AtABI3</italic>. When the <italic>Arabidopsis gs1</italic> mutant was transformed with the <italic>BnABI3</italic> gene, the transformed plants produced seeds that turned yellow and acquired desiccation tolerance. Moreover, <italic>BnABI3</italic> regulates seed coat development and mucilage secretion by directly targeting the <italic>AtMUM1</italic> and <italic>AtGATL5</italic> genes. In addition, we showed that <italic>BnABI3</italic> expression rescued <italic>gs1</italic> freezing-induced green seed coloration by targeting <italic>AtSGR1/2</italic> in transgenic <italic>Arabidopsis</italic>. <italic>BnABI3</italic> is also involved in lateral root development and conferred a novel interaction between ABA and auxin signaling in roots. The potential role of <italic>ABI3</italic> protein in endoplasmic reticulum homoeostasis was also tested. Altogether, our results indicated that <italic>BnABI3</italic> mediates both plant development and the stress response.</p>