Dual Defense Strategy of GhRAP1 Gene: Coordinating Antibiosis and Antixenosis to Enhance Aphid Resistance in Plants.

The cotton aphid (Aphis gossypii) is a major pest detrimental to cotton production, and the development of control strategies has been a key research focus. NBS-LRR-type disease resistance genes, the predominant class of R genes, have been found to confer dual resistance against aphids. This study identified 88 resistance to aphid protein (RAP) genes in Gossypium hirsutum (G. hirsutum), other cotton species, and Arabidopsis thaliana (A. thaliana), with a focus on G. hirsutum resistance to aphid protein (GhRAP1). Its expression was upregulated following aphid infestation. Functional analysis demonstrated that silencing GhRAP1 in cotton rendered plants more susceptible to aphid infestation, while its overexpression in A. thaliana effectively deterred aphid feeding and reduced their survival and reproductive rates. Electrical penetration graph (EPG) results further revealed that GhRAP1-overexpressing plants enhanced the mechanical resistance against aphid penetration and significantly shortened the duration of phloem feeding. These findings collectively indicate that GhRAP1 confers plant resistance through both antixenosis and antibiosis mechanisms, providing crucial insights for developing novel aphid control strategies.