NBR1a mediates root-knot nematode resistance by modulating antioxidant system, jasmonic acid and selective autophagy in Solanum lycopersicum

Root -knot nematodes (RKNs; Meloidogyne incognita) are recognized as the most destructive plant pathogenic nematodes, posing a significant threat to global food security. Selective autophagy, a conserved process for degrading and recycling cellular components, plays an essential role in the growth, development, and immune response of eukaryotes. The established role of selective autophagy receptors in plant responses to diverse stresses is well recognized, however, their precise functions in plant defense against RKN infection remain largely unexplored. This study investigates the response of nine selective autophagy receptors in tomato (Solanum lycopersicum) to RKN infection. Notably, the relative expression of NBR1a, PUX7a and ATI3d showed significant induction. NBR1a-silenced plants and nbr1a mutants both exhibited heightened sensitivity to RKN compared to the pTRV control and wild -type (WT) plants, while silencing of PUX7a and ATI3d genes did not exhibit increased sensitivity to RKN compared to the pTRV control plants. Furthermore, antioxidant enzyme activity, jasmonic acid (JA), as well as the number of autophagosomes and autophagic vesicles in root tip cells, did not exhibit significant induction in the nbr1a mutant upon RKN infection, in contrast to WT plants. These findings strongly suggest that the selective autophagy receptor NBR1a enhances tomato resistance against RKNs by modulating the antioxidant system, JA and selective autophagy.