Effects of Salinity and Abscisic Acid on Lipid Transfer Protein Accumulation, Suberin Deposition and Hydraulic Conductance in Pea Roots

Abstract

Lipid transfer proteins (LTPs) participate in many important physiological processes in plants, including adaptation to stressors, e.g., salinity. Here we address the mechanism of this protective action of LTPs by studying the interaction between LTPs and abscisic acid (ABA, a “stress” hormone) and their mutual participation in suberin deposition in root endodermis of salt-stressed pea plants. Using immunohistochemistry we show for the first time NaCl induced accumulation of LTPs and ABA in the cell walls of phloem paralleled by suberin deposition in the endoderm region of pea roots. Unlike LTPs which were found localized around phloem cells, ABA was also present within phloem cells. In addition, ABA treatment resulted in both LTP and ABA accumulation in phloem cells and promoted root suberization. These results suggested the importance of NaCl-induced accumulation of ABA in increasing the abundance of LTPs and of suberin. Using molecular modeling and fluorescence spectroscopy we confirmed the ability of different plant LTPs, including pea Ps-LTP1, to bind ABA. We therefore hypothesize an involvement of plant LTPs in ABA transport (unloading from phloem) as part of the salinity adaptation mechanism.

Genome-wide association analysis for drought tolerance and associated traits in faba bean (Vicia faba L.)

“…Further candidates associated with HSW in drought conditions include the lipid-transfer protein (LTP) DIR1, the transcription termination factor MTEF1 and a xyloglucan endotransglucosylase/hydrolase protein. LTPs are thought to be involved in plant defense responses ( Safi et al., 2015 ) and their expression is induced by biotic and abiotic stresses, including disease, salinity, temperature and drought ( Safi et al., 2015 ; Akhiyarova et al., 2021 ; Duo et al., 2021 ; Zhao et al., 2021 ). It is also well established that drought tolerance is regulated by the mitochondrial transcription termination factors (MTERFs).…”

The Effects of Rhizosphere Inoculation with Pseudomonas mandelii on Formation of Apoplast Barriers, HvPIP2 Aquaporins and Hydraulic Conductance of Barley

“…It was important to find out how bacterial treatment could affect the formation of apoplastic barriers and abundance of aquaporins. Previously, ABA stimulated the formation of apoplastic barriers in pea plants [ 33 ] and increased aquaporins activity in many species [ 8 , 20 , 34 ]. In the present work, immunolocalization showed an increased abundance of ABA in the root sections of the bacteria-treated plants, which was most noticeable in the region of the endodermis and exodermis.…”

Features and Possible Applications of Plant Lipid-Binding and Transfer Proteins

“…In vitro binding experiments showed that LTPs can bind both saturated and unsaturated free fatty acids (C12–C20) or the fatty acyl chains presented in various molecules as in lysophosphatidylcholine (LPC), phosphatidylglycerol (PG), acyl coenzyme A (CoA), and cerebrosides (galactolipids), and it can bind jasmonic and abscisic acids, prostaglandin B2, molecules of organic solvents, and some drugs [ 18 , 21 , 23 , 24 , 25 , 26 ]. For many LTPs, in vitro binding data show that the proteins lack specificity in binding to ligands.…”