Abstract: The pepper gene Cacl-6468 is a novel ethylene-responsive proteinase inhibitor gene，from the nematode-resistance pepper HDA149（Capsicum annuum），belongs to the Potato InhibitorⅠsupper gene family，and has close genetic homology with potato ethylene-responsive proteinase inhibitor. The expression levels of Cacl-6468 in HDA149 were significantly affected by the population kinds of Meloidogyne incognita. For virulence population of M. incognita，Cacl-6468 was down-regulated significantly after 12 h infection，and reached the lowest level at seven days；while for avirulence population，the expression level was significantly up-regulated after 12 h infection，and reached the highest level at three days. Using virus-induced gene silencing（VIGS）technique，it was proved that the knock-down of Cacl-6468 could promote avirulent population to overcome the resistance of pepper HDA149，and developed some galls and egg masses，but the numbers were significantly lower than that of virulent population. The VIGS test also confirmed that Cacl-6468 negatively regulated ethylene signaling pathway，but had no significant effect on salicylic acid signaling pathway. In addition，the early pathological observation and chemotaxis test showed that VIGS treatment of Cacl-6468 enhanced the attraction of pepper root to M. incognita，and promoted early stage infection. The ethylene release of pepper was detected by GC-MS，showed that inhibition of Cacl-6468 expression could enhance the ethylene release of pepper. qPCR results suggested that Cacl-6468 is involved in the resistance regulation of pepper to M. incognita through ethylene signaling pathway，decreased the expression level of Cacl-6468 can increase the susceptibility，and weaken the resistance of pepper HDA149.

Key words: ethylene-responsive proteinase inhibitor, Capsicum annuum, Meloidogyne incognita, resistance