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

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 coi1mutant 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 coi1-5mutant (COI1G98D) contains adequate COI1 protein (∼60% of wild-type). Interestingly, the low basal level of COI1E543Kin the coi1-8mutant (∼10% of wild-type COI1 level) is sufficient for maintaining male fertility (∼50% of wild-type fertility); the coi1-2mutant with low level of COI1L245F(∼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 coi1-2and coi1-8are defective in the other JA responses (root growth, anthocyanin accumulation, and plant response to the pathogen PstDC3000 infection).