Amino acid substitutions of GLY98, LEU245 and GLU543 in COI1 distinctively affect jasmonate-regulated male fertility in Arabidopsis

Abstract

Jasmonate (JA) regulates various plant defense and developmental processes. The F-box protein CORONATINE INSENSITIVE 1 (COI1) perceives JA signals to mediate diverse plant responses including male fertility, root growth, anthocyanin accumulation, and defense against abiotic and biotic stresses. In this study, we carried out genetic, physiological and biochemical analysis on a series of coi1 mutant alleles, and found that different amino acid mutations in COI1 distinctively affect JA-regulated male fertility in Arabidopsis. All the JA responses are disrupted by the COI1 mutations W467 in coi1-1, Q343 (coi1-6), G369E (coi1-4), G98D (coi1-5), G155E (coi1-7), D452A (coi1-9) and L490A (coi1-10), though the coi1-5 mutant (COI1G98D) contains adequate COI1 protein (~ 60% of wild-type). Interestingly, the low basal level of COI1(E543K) in the coi1-8 mutant (~ 10% of wild-type COI1 level) is sufficient for maintaining male fertility ( ~50% of wild-type fertility); the coi1-2 mutant with low level of COI1(L245F) (~ 10% of wild-type) is male sterile under normal growth condition (22°C) but male fertile (~ 80% of wild-type fertility) at low temperature (16°C); however, both coi1-2 and coi1-8 are defective in the other JA responses (root growth, anthocyanin accumulation, and plant response to the pathogen Pst DC3000 infection).