TITLE:
Phytohormone-Induced Resistance against Xanthomonas axonopodis PV. citri in Citrus aurantifolia
AUTHORS:
Shahran Ahmed Nayem, M. Salahuddin M. Chowdhury, F. M. Aminuzzaman, Belal Hossain, Sahadat Ali
KEYWORDS:
Citrus Canker, Induce Resistance, Phenolic Compounds, Phytohormone
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.8 No.5,
April
26,
2017
ABSTRACT: Citrus
canker is a perilous disease caused by Xanthomonas
axonopodis pv. citri (Xac) which is hardly manageable. Till now, chemicals used
against Xac either proved less effective against the disease or hazardous for
environment. In this study, we investigated how phytohormones such as Salicylic
acid (SA, 3 mM), Jasmonic acid (JA, 0.3 mM), 3-indolacetonitrile (IAN, 0.6 mM),
Nicotinic acid (NA, 5 mM), Folic acid (FA, 0.5 mM) influenced canker disease.
Disease severity and lesion diameter were significantly mitigated by exogenous
application of these phytohormones compared with water (control) accompanied by the increase of latent period. However, these phytohormones did not show any in
vitro antimicrobial properties against Xac. Concomitant with boosted
resistance, phytohormones treated
leaves showed the higher level of phenyl ammonia lyase (PAL) activity. Besides, total
phenolic compounds (TPC) and potassium contents were also higher in
phytohormone treated plants compared with control. Phytohormones showed the significant and better
performance on disease mitigation than control among which, SA showed the highest performance while JA and INA
showed the moderate performance. However, NA and FA showed the lowest performance. This result recommended that
application of some phytohormones had elicited some biochemical and
physiological events which induced the resistance against Xac.