Characterization of Pentatricopeptide Repeat (PPR) Gene That Linked to Immature Fiber Phenotype

Cotton fiber maturity is an important factor for determining the value of cotton. Molecular mechanisms and pathways regulating fiber maturity are not well understood. A pair of near isogenic lines, immature fiber (im) mutant and Texas Marker-1 (TM-1) has been suggested as a model system for studying molecular mechanisms regulating fiber maturity since their fiber maturity values are different. Our group previously showed that a 22bp deletion in a pentatricopeptide repeat (PPR) gene is completely linked to the immature fiber phenotype in a population of 2,837 F₂ plants via a mapping-by-sequencing method. To test if the PPR gene affects the fiber maturity, we constructed two different virus induced gene silencing (VIGS) constructs and infected into multiple TM-1 plants for suppressing the PPR transcripts. Genetic and phenotypic analyses of the infected TM-1 plants showed that one construct specifically knocked down the PPR gene expression and successfully reduced fiber maturity and MIC values. Detailed results will be presented.