SlABCG9 Functioning as a Jasmonic Acid Transporter Influences Tomato Resistance to Botrytis cinerea

Jasmonic acid (JA) is crucial for plant stress responses,
which
rely on intercellular jasmonate transport. However, JA transporters
have not been fully identified, especially in tomato (Solanum lycopersicum L.). This study reveals that
plasma-membrane-localized protein SlABCG9 in tomato regulates fruit
resistance to Botrytis cinerea. Transcriptomic
analysis indicated that the SlABCG9 expression was
significantly upregulated after B. cinerea infection. Assays using Xenopus oocytes,
yeast cell sensitivity, and JA-inhibited primary root growth confirmed
that SlABCG9 functions as a JA influx transporter. The knockout mutant
lines of SlABCG9 showed decreased JA contents, suppressed
defense gene PDF1.2’s expression, reduced
antioxidant enzyme activity, and severe disease symptoms compared
to wild-type controls. Our findings provide new knowledge for understanding
how the JA transporter and signaling pathway are involved in the biotic
stress responses and improve the resistant ability against pathogen
infections.