Biochemical and molecular changes in common bean during anthracnose disease development

Abstract

The aim of this study was to investigate changes in defense molecules andother metabolites related to phenyl propanoid in common bean varietiesimpartingdifferentlevelsofresistancetoinfectioncausedbyhemibiotrophicfungusColletotrichum lindemuthianum (T1 and T2 from Bhaderwah and ITCC, IARI, Delhi, respectively) and alsoto determine the relation of the compounds to pathogen tolerance. Anthracnose resistant (VL63)andsusceptiblevarieties(BR104andBR50)wereinoculatedundergreenhouseconditionsandassessedforoxidativestressindices,biochemicalindices,antioxidantcomponent,antioxidantenzymes,secondarymetabolites,SDSPAGEprofileofproteins,ionchromatographic profile of phenolic and sugars related to plant defense post infection. Leafsampleswerecollectedonthe3rd, 6thand 9thdays after infection. Higher electrolyteleakage,malondialdehyde,totalsolublesugarandtotalfreeaminoacidwereobservedinsusceptible varieties corresponding to resistant.The infected leaves of VL 63 showed higheractivityofsuperoxidedismutase,peroxidases,polyphenoloxidases,catalase,ascorbateperoxidase, phenyl ammonium lyase, ascorbic acid and hydrogen peroxide level than BR 104and BR 50 compared to control, whereas the reduction rate of carotenoid, chlorophyll a,chlorophyllbandtotalchlorophyllweremorepromptinsusceptiblecultivars. Thevarietywitha greater level of resistance was superior to the susceptible in regard to secondary metabolitelevels in shoot and root. In response to infection total phenols, flavonoid, tannin, alkaloid andsaponinwerehigherinleavesthanroot.SDSPAGEofleafproteinsexpoundednewpolypeptiderangingfrom119kDa to 25.4kDawhereasrootproteinpolypeptidefrom119kDa to 17.7 kDa. A total seven of sugars i.e. myo-inositol, mannitol, trehalose, fructose,glucose, sucrose and stachyose was detected in all shoot samples of varieties except raffinosewhichappearedexclusivelyinrootsofVL63.BR50showed22.42-foldincreaseinchlorogenic acid with T1 while highest fold of 2.0 increase in chlorogenic acid was recorded inVL63.TheexpressionlevelsoftwogenesCHSandPALwerec