Local and systemic responses conferring acclimation of Brassica napus roots to low phosphorus conditions

Abstract

Due to the non-uniform distribution of inorganic phosphate (Pi) in the soil, plants modify their root architecture to improve acquisition of this nutrient. In this study, a split-root system was employed to assess the nature of local and systemic signals that modulate root architecture of Brassica napus grown with non-uniform Pi availability. Lateral root (LR) growth was regulated systemically by non-uniform Pi distribution, by increasing the density of the second-order LR (2˚LR) in compartments with luxury Pi supply but decreasing the 2˚LR density in compartments with low Pi availability. Transcriptomic profiling identified groups of genes regulated, both locally and systemically, by Pi starvation. The number of systemically induced genes was greater than the number that was locally induced and included genes related to abscisic acid (ABA) and jasmonic acid (JA) signalling pathways, reactive oxygen species (ROS) metabolism, sucrose, and starch metabolism. Physiological studies confirmed the involvement of ABA, JA, sugars, and ROS in the systemic Pi starvation response. The data reported reveal the mechanistic basis of local and systemic responses of B. napus to Pi starvation and provide new insights into the molecular and physiological basis of root plasticity.

Brassinosteroid signaling regulates phosphate starvation‐induced malate secretion in plants

“…Local Pi signaling, which is controlled by the Pi level in the environment, regulates the secretion of organic acids and root architecture remodeling (Thibaud et al, 2010). Hormone and ROS signals mediate the local Pi signaling pathway (Abel, 2017; Du et al, 2022; Li et al, 2022). Unlike other hormones, BRs cannot be transported over long distances in plants, making them suitable for regulating local Pi signaling (Symons and Reid, 2004; Symons et al, 2008).…”

“…Secretion of acid phosphatases, accumulation of Pi transporters, and expression of phospholipid remodeling genes is mainly regulated by systemic Pi signaling, whereas stress and hormone response genes are mainly regulated by local Pi signaling (Thibaud et al, 2010; Du et al, 2022; Li et al, 2022). The systemic signal sensed by Suppressor of Yeast gpa1 (Syg1), yeast Phosphatase 81 (Pho81), and human Xenotropic and Polytropic Retrovirus receptor 1 (Xpr1) (SPX) domain‐containing proteins, which negatively regulate the activity of PHOSPHATE RESPONSE 1 (PHR1) and closely related transcription factors, is determined by the intracellular Pi status (Wild et al, 2016; Puga et al, 2017).…”

“…The systemic signal sensed by Suppressor of Yeast gpa1 (Syg1), yeast Phosphatase 81 (Pho81), and human Xenotropic and Polytropic Retrovirus receptor 1 (Xpr1) (SPX) domain‐containing proteins, which negatively regulate the activity of PHOSPHATE RESPONSE 1 (PHR1) and closely related transcription factors, is determined by the intracellular Pi status (Wild et al, 2016; Puga et al, 2017). Plants employ local Pi signaling to sense the external Pi level, which is usually unevenly distributed in soil (Thibaud et al, 2010; Li et al, 2022). Unlike the systemic signal, the local Pi sensors and signaling pathway remain largely unknown (Abel, 2017).…”

PHR1 involved in the regulation of low phosphate‐induced leaf senescence by modulating phosphorus homeostasis in Arabidopsis

“…To evaluate Pi and total P dynamic change in LP-induced senescing leaves, the new (young) and first (old) rosette leaves of Arabidopsis treated with LP stress for 3 days were collected and used for Pi and total P content assay. The Pi content was measured using the previously described method (Li et al, 2022). Briefly, the fresh rosette leaves (0.05 g) were homogenized with 50 μL H 2 SO 4 (5 M) and 950 μL H 2 O.…”

Trade‐offs between root‐secreted acid phosphatase and root morphology traits, and their contribution to phosphorus acquisition in Brassica napus

“…Brassica napus is one of the most important and profitable oil crops in the world (Angelovič et al, 2013), but it is sensitive to low soil P availability (Ding et al, 2012; Duan et al, 2020; Shi et al, 2013; Yuan et al, 2016). Root morphology traits of B. napus in response to low P availability have been well studied (Duan et al, 2021; Li et al, 2022; Wang et al, 2017; Xu et al, 2022; Xu et al, 2023; Yang et al, 2010), and wide genotype variations in root morphology traits and seed yield (SY) are reported among a large association panel of B. napus with diverse genetic backgrounds under P‐deficient conditions (Wang et al, 2017; Liu et al, 2023). Recently, Duan et al (2020) report that rhizosphere APase activity of B. napus increased from the leaf development stage to pod development in soils with low P availability, especially during the leaf development stage.…”