544 / 2019-03-14 18:55:26

Functional analysis of callose deposition in Arabidopsis thaliana under phosphate starvation

callose,stress,root,phosphate starvation response,anthocyanin,Arabidopsis thaliana,phosphate uptake,glucan synthase

全体主题 > Abiotic Stress

Plants deposit a β-1,3 glucan polymer, called callose, in the cell wall in responses to biotic and abiotic stresses. Callose is synthesized at the plasma membranes by glucan synthase-like (GSL) enzymes. Stress-induced callose deposition is likely to provide a physical barrier to halt pathogen invasion and reduce the permeability of plasmodesmata. Callose deposition is also induced during phosphate starvation response (PSR), but the physiological significance and underlying mechanisms remain poorly understood. Here, we report that PSR-associated callose deposition is largely retained in Arabidopsis plants lacking the two major PSR pathways defined by the transcription factors PHR1/PHL1 and the ferrooxidases LPR1/LPR2. This suggests the involvement of a novel low-phosphate sensing pathway in callose deposition. Notably, one member of 12 GSL genes annotated in Arabidopsis thaliana is required for callose deposition during PSR. This offers an unprecedented opportunity to unambiguously assess the role for callose in PSR.
The gsl mutant plants display increases in primary root growth inhibition and anthocyanin accumulation under low phosphate conditions, pointing to functional linkage between these outputs and callose deposition during PSR. Possible alterations in plant associations with beneficial and pathogenic fungi are currently being tested in the callose-deficient plants.