TuMV triggers stomatal closure but reduces drought tolerance in Arabidopsis

MANACORDA, CARLOS AUGUSTO; GUDESBLAT, GUSTAVO; SUTKA, MOIRA; ALEMANO, SERGIO; PELUSO, FRANCO; ORICCHIO, PATRICIO; BAROLI, IRENE; ASURMENDI, SEBASTIÁN

PLANT, CELL AND ENVIRONMENT (PRINT)

WILEY-BLACKWELL PUBLISHING, INC

Año: 2021

0140-7791

Compatible plant viral infections are a common cause of agricultural losses worldwide.Characterization of the physiological responses controlling plant water managementunder combined stresses is of great interest in the current climate changescenario. We studied the outcome of TuMV infection on stomatal closure and waterbalance, hormonal balance and drought tolerance in Arabidopsis. TuMV infectionreduced stomatal aperture concomitantly with diminished gas exchange rate, dailywater consumption and rosette initial dehydration rate. Infected plants overaccumulatedsalicylic acid and abscisic acid and showed altered expression levels ofkey ABA homeostasis genes including biosynthesis and catabolism. Also the expressionof ABA signalling gene ABI2 was induced and ABCG40 (which imports ABA intoguard cells) was highly induced upon infection. Hypermorfic abi2-1 mutant plants,but no other ABA or SA biosynthetic, signalling or degradation mutants testedabolished both stomatal closure and low stomatal conductance phenotypes causedby TuMV. Notwithstanding lower relative water loss during infection, plants simultaneouslysubjected to drought and viral stresses showed higher mortality rates thanmock-inoculated drought stressed controls, alongside downregulation of droughtresponsivegene RD29A. Our findings indicate that despite stomatal closure triggeredby TuMV, additional phenomena diminish drought tolerance upon infection.