Comparative study on Pseudaulacaspis pentagona resistance of four different cultivars of kiwifruit

Kiwifruit is a common and popular fruit around the world. However, white peach scale (Pseudaulacaspis pentagona [Targioni‐Tozzetti]), a scale insect with a wide range of hosts, seriously affects the yield and quality of kiwifruit. To investigate the differences in resistance of different kiwifruit cultivars to P. pentagona, cellular structure and gene expression assays were used to explain the mechanism. Based on the stability of the infestation rate, we selected four cultivars from 50 kiwifruits for in‐depth study, including ‘LC‐04285’, ‘CF‐3’, ‘DA‐7B’ and ‘Hayward’. The anatomical structure of the canes analysis revealed that the resistant cultivar ‘LC‐04285’ had thicker cuticle, denser epidermis and cortex. The expression levels of genes related to cuticle synthesis and formation of epidermis and cortex were also higher in ‘LC‐04285’. Further investigation revealed that Jasmonic acid (JA) receptors COI1 were highly expressed in ‘LC‐04285’. However, the expression levels of AcJAZs were higher in the susceptible cultivar ‘Hayward’. Besides, AcICS, AcPAL4, AcPAL5 and AcNPRs, which were involved in salicylic acid (SA) synthesis and SA response, were also highly expressed in ‘LC‐04285’. Our results preliminarily revealed the mechanism of kiwifruit resistance to P. pentagona at the molecular and cellular levels. This study provided useful guidance for breeding insect‐resistant kiwifruit in the future. We studied four cultivars of kiwifruit, which displayed varying degrees of resistance to the P. pentagona naturally. At the cellular level, the resistant variety ‘LC‐04285’ had thicker cuticle, denser epidermis and cortex. In addition, transcription analysis showed that ‘LC‐04285’ might have stronger JA/SA‐induced pest resistance.