Secretory Phospholipases A2 in Durum Wheat (Triticum durum Desf.): Gene Expression, Enzymatic Activity, and Relation to Drought Stress Adaptation

Abstract

Phospholipases A2 (PLA2s) are known to mediate signaling cascades during plant growth and development, as well as biotic and abiotic stress responses. In this context, the present study provides extensive characterization of specific PLA2s in durum wheat, and assesses their involvement in durum wheat response to drought stress. In durum wheat leaves, four full-length expressed sequences encoding putative PLA2s were isolated and characterized as belonging to the class of secretory PLA2s (sPLA2s): TdsPLA2I, TdsPLA2II, TdsPLA2III and TdsPLA2IV. PLA2 activity was also detected, the characteristics of which resemble those of previously characterized plant sPLA2s: strong preference for phospholipids; requirement for millimolar Ca2+ concentrations; optimal activity at basic pH; heat stability; and inhibition by the reducing agent dithiothreitol. With drought stress imposed at both the vegetative and reproductive stages, accumulation of TdsPLA2I and TdsPLA2III transcripts, and to a lesser extent of TdsPLA2IV transcript, paralleled increased PLA2 activity; both transcript levels and enzymatic activity decreased as a consequence of stress recovery. Consistently, free fatty acid analysis of drought-stressed leaves revealed increased linoleate, linolenate and palmitate contents, which were reversed by plant re-watering. Overall, these findings strongly suggest that there are inducible sPLA2 isoforms in durum wheat that have roles in orchestrating the plant response to drought stress.

Increased fire frequency promotes stronger spatial genetic structure and natural selection at regional and local scales in Pinus halepensis Mill

“…A second nonsynonymous SNP was located in a region coding for a phospholipase A2-like protein. Phospholipases A2 (PLA2s) mediate signalling cascades during plant growth and development, and intervene in biotic and abiotic stress responses, particularly in drought stress (Verlotta et al, 2013). We further detected a synonymous substitution in a cobra-like gene probably involved in cell formation and cellulose content (Thumma et al, 2009) and a mutation in an untranslated region of a trehalose-6-phosphate synthase-coding gene probably involved in abiotic stress responses (Iordachescu and Imai, 2008).…”

Recombinant Lipases and Phospholipases and Their Use as Biocatalysts for Industrial Applications

“…Currently, the PLA 2 superfamily consists of several groups of enzymes that are classified into five different classes: the secretory Ca 2+ -dependent PLA 2 s (sPLA 2 s), the cytosolic, Ca 2+ -dependent PLA 2 s (cPLA 2 s), the cytosolic, Ca 2+ -independent PLA 2 s (iPLA 2 s), the platelet-activating-factor acylhydrolases (PAF-AHs), and the lysosomal PLA 2 s (L-PLA 2 s) ( Table 3 ) [ 43 ]. The sPLA 2 s (14–18 kDa) have been identified in sources as diverse as animal venoms, mammalian tissues, plants, yeasts and fungi, bacteria and a parvovirus [ 43 , 44 , 45 , 46 ]. The cPLA 2 s (61–114 kDa) and iPLA 2 s (28–146 kDa) have been identified in human and mouse.…”

Molecular details of secretory phospholipase A2 from flax (Linum usitatissimum L.) provide insight into its structure and function

“…Several studies have highlighted the involvement of sPLA 2 in wounding and pathogen attack 45 , cold and salinity tolerance 46 . Recently several isoforms of sPLA 2 s were reported to be highly up-regulated during water stress in wheat 15 , rice 14 and arabidopsis 46 . In wheat, PLA 2 activity concomitantly increases during drought stress 15 while sPLA 2 s have been implicated in hyperosmotic stress in Chlamydomonas 47 .…”

“…PLA 2 activity was evaluated using spectrophotometric method based on PLA 2 /lipoxygenase (LOX) coupled reactions 15 . The PLA 2 activity was assayed by addition of the recombinant protein to 4 E.U.…”

“…In plants, sPLA 2 s are ubiquitous and are extensively studied enzymes known to be involved in a suite of signal transduction pathways 8 , 9 . They play myriad roles in biological and metabolic processes leading to growth 10 , development 11 , 12 including plant defence 13 and imparting tolerance against abiotic stress 14 , 15 .…”