P-378 - NAC Transcription Factors Positively Regulate Kiwifruit Resistance Against Pseudomonas syringae pv. actinidiae

Kiwifruit bacterial canker, caused by Pseudomonas syringae pv. actinidiae (Psa), poses a serious threat to global kiwifruit production. In this study, 44 diploid Actinidia chinensis var. chinensis F1 hybrid lines derived from a cross between two A. chinensis var. chinensis lines were screened, acquiring resistant RH12 and susceptible SH14 offspring. Transcriptome and weighted correlation network analysis suggest that NAC transcription factors play an important role in host immunity. Transgenic materials resistance evaluation identified AcNAC10, AcNAC44, and AcNAC80 as positive regulators of kiwifruit immunity. AcNAC10 modulated jasmonic acid (JA) homeostasis by regulating AcLOX3 expression, its silencing disrupted JA balance and compromised resistance. Furthermore, AcNAC10 was activated by AcTGA07, maintaining JA homeostasis through AcNAC10-AcLOX3, highlighting its crucial role in immunity. AcNAC80 improved resistance by elevated reactive oxygen species (ROS) accumulation, antioxidant enzyme activities, and salicylic acid (SA) levels. This resistance mechanism was confirmed in transgenic tomato and Arabidopsis. DAP-seq and transcriptomic showed AcNAC80 binds CACG motifs in promoters, directly activating resistance genes like AcSARD1, AcEXPA4, and AcRPP13. This study revealed that NAC transcription factors activate SA and inhibit JA, providing dual regulation of kiwifruit immunity against Psa and offering critical insights for breeding disease-resistant kiwifruit varieties.