SlWRKY45 Interacts with Jasmonate-ZIM Domain Proteins to Negatively
Regulate Defense Against Root Knot Nematode Meloidogyne incognita in
Root knot nematode (RKN), a kind of plant parasitic nematodes, leads to
large reduction of crop yield, and seriously damages the agricultural
production. The phytohormone jasmonates (JAs) act as important signals
to regulate resistance against multiple abiotic and biotic stresses.
However, little is known about the mechanism of JA-mediated defense
responses against RKN in tomato. In this study, we found that the WRKY
transcription factor SlWRKY45 interacts with most of the Jasmonate-ZIM
domain proteins (JAZs) in yeast and plant. Overexpression of
SlWRKY45 decreased plant resistance to RKN Meloidogyne
incognita with increased gall index. We further generated
slwrky45 mutants using the CRISPR/Cas9 technology, and discovered
that the gall index and the number of nematodes and females in
slwrky45 mutants are significantly reduced compared with wild
type, as inoculated with RKN Meloidogyne incognita. Moreover, the
contents of jasmonic acid and JA-isoleucine (JA-Ile) were highly
increased in slwrky45 mutants with RKN Meloidogyne
incognita infection compared with wild type. Furthermore, EMSA, and
Dual-LUC assays demonstrated that SlWRKY45 directly binds and represses
jasmonate biosynthesis gene ALLENE OXIDE CYCLASE ( AOC).
Overall, our findings reveled that JAZ-interaction protein SlWRKY45
negatively controls plant defense against RKN Meloidogyne
incognita by the regulation of JA biosynthesis in tomato.