Effects of Phospholipase Dε Overexpression on Soybean Response to Nitrogen and Nodulation

Abstract

Nitrogen is a key macronutrient to plant growth. We found previously that increased expression of phospholipase Dε (PLDε), which hydrolyzes phospholipids into phosphatidic acid (PA), enhanced plant growth under nitrogen deficiency in Brassicaceae species Arabidopsis and canola. The present study investigated the effect of AtPLDε-overexpression (OE) on soybean (Glycine max), a species capable of symbiotic nitrogen fixation. AtPLDε-OE soybean plants displayed increased root length and leaf size, and the effect of AtPLDε-ΟΕ on leaf size was greater under nitrogen-deficient than -sufficient condition. Under nitrogen deficiency, AtPLDε-OE soybean plants had a higher chlorophyll content and activity of nitrogen assimilation-related enzymes than wild-type soybean plants. AtPLDε-OE led to a higher level of specific PA species in roots after rhizobium inoculation than wild type. AtPLDε-OE soybean plants also increased seed production under nitrogen deprivation with and without nodulation and decreased seed germination in response to high humidity storage and artificial aging. These results suggest that PLDε promotes nitrogen response and affects adversely seed viability during storage.

Identification of phospholipase Ds and phospholipid species involved in circadian clock alterations using CRISPR/Cas9-based multiplex editing of Arabidopsis

“…They can be activated differently in response to diverse stimuli, and these differences account for the highly dynamic nature of PA contents and compositions depending on environmental conditions (Hong et al, 2016; Ali et al, 2022; Deepika and Singh, 2022; Kolesnikov et al, 2022). This is evidenced by, in addition to early studies, recent reports showing a rapid accumulation of PA by PLDα1 in response to magnesium stress and rhizobium infection, β2 during hypoxia, δ under heat and osmotic stress, and ε and ζ2 in nitrogen and phosphate deficit, respectively, with a few specific PA molecular species contributing to the accumulation of total PA in some cases (Su et al, 2018; Premkumar et al, 2019; Song et al, 2020; Kocourková et al, 2021; Liu et al, 2021; Zhang et al, 2021; Kim et al, 2022; Yao et al, 2022 a and b). Not only for plants to cope with unfavorable conditions, PLDs are also required for normal physiological processes mediated by their direct interaction with effector proteins, regulation of cytoskeletal dynamics and vesicle trafficking, and membrane remodeling and degradation (Hong et al, 2016; Deepika and Singh, 2022).…”

Phospholipid Signaling in Crop Plants: A Field to Explore

“…The overexpression of Arabidopsis PLDε (also named PLDα4) led to a stimulation of rapeseed ( Brassica napus ) [ 91 ] and soybean ( Glycine max ) [ 92 ] growth under nitrogen deficiency. This effect was attributed to the increased activity of enzymes involved in nitrate uptake and assimilation in PLDε-overexpressing lines.…”