Mechanism of drought and salt tolerance of <italic>OsLPL2/PIR </italic>gene in rice

Abstract

<p id="C3">Drought threatens global agricultural production and limits the prospects for sustainable agricultural development. Plant leaf epidermis plays a vital role in the process of growth, development, and resistance to adversity stress, and water and gas exchange with the external environment. In this study, compared with the wild-type Zhonghua 11 (ZH11), we found that mutants <italic>less pronounced lobe epidermal cell 2-1</italic> (<italic>lpl2-1</italic>) and<italic> less pronounced lobe epidermal cell 2-2</italic> (<italic>lpl2-2</italic>) were more sensitive to drought and salt stress response, and the survival rate after rewatering was extremely significantly reduced, which was less than half of the control. Compared with ZH11, <italic>lpl2-1 </italic>and<italic> lpl2-2</italic> had shorter plant height, shorter root length, significantly increased stomatal density and stomatal openings in the same phyllodes, and the serrated lobe of the epidermal cell margin becomes smoother, and the epidermal cell nesting was not tight, which might result in faster and more water loss of <italic>lpl2-1</italic> and <italic>lpl2-2</italic> than ZH11. The water loss experiment of separated leaves also proved that the water loss rate of <italic>lpl2-1</italic> and <italic>lpl2-2</italic> leaves was higher than that of the ZH11 in equal time. Overexpression of <italic>OsLPL2</italic> was transferred into <italic>lpl2-1</italic>, and the <italic>OE-OsLPL2</italic>/<italic>lpl2-1</italic> transgenic positive plants recovered the smooth epidermis of <italic>lpl2-1</italic> and the sensitive phenotype to drought and salt stress. These results showed that <italic>OsLPL2</italic> gene not only controlled the microfilament synthesis and morphogenesis of rice epidermal cells, but also played a key role in response to plant stress by regulating stomatal density, stomatal conductance, and root growth and development. This study provides a theoretical basis for revealing the molecular regulation mechanism of <italic>OsLPL2</italic> in response to drought stress in rice.