USDA Agricultural Research Service, San Joaquin Valley Agricultural Sciences Center, Parlier, CA, USA.
Present Address: Department of Entomology, Pennsylvania State University, University Park, PA, USA.
J Econ Entomol. 2021 Oct 13;114(5):1991-2008. doi: 10.1093/jee/toab141.
The glassy-winged sharpshooter, Homalodisca vitripennis (Germar) (Hemiptera: Cicadellidae: Cicadellinae), is an introduced vector of the xylem-dwelling bacterium Xylella fastidiosa Wells et al. (Xanthomonadales: Xanthomonadaceae) in California. Once acquired, X. fastidiosa colonizes the functional foregut of the vector. Bacteria can be inoculated directly into grapevine xylem during the xylem cell acceptance process in sharpshooter stylet probing, represented by the X wave using electropenetrography (EPG). Since 2001, an effort has been underway to develop PD-resistant grapevines, Vitis vinifera L., through classical breeding of various species of resistant wild grapevines with more susceptible V. vinifera. The present study used EPG to compare H. vitripennis stylet probing behaviors in a factorial experiment between V. champinii (a V. candicans/V. rupestris natural hybrid with moderate trichomes) and V. vinifera cv. 'Chardonnay' (which lacks trichomes) that had been gently scraped to remove trichomes or was not scraped. Results showed that sharpshooters performed significantly more X waves/X. fastidiosa inoculation behaviors of overall longer duration on Chardonnay than on V. champinii, regardless of shaving or not-shaving to remove trichomes. In addition, trichomes caused more frequent standing/walking/test-probing behaviors on V. champinii, whose xylem was rapidly accepted for sharpshooter ingestion once probing began. Thus, EPG can detect a novel type of grapevine resistance to X. fastidiosa-to the vector's probing process and inoculation of bacteria-in addition to the bacterial infection and symptom development processes that are the basis for most resistance breeding today. Future research could use EPG to screen grapevines for this novel type of resistance.
玻璃脆盲蝽，Homalodisca vitripennis（Germar）（半翅目：叶蝉科：叶蝉亚科），是加利福尼亚州木质部细菌 Xylella fastidiosa Wells 等人（Xanthomonadales：Xanthomonadaceae）的传入媒介。一旦获得，X. fastidiosa 就会在媒介的功能前肠中定植。细菌可以通过电穿孔（EPG）中的 X 波在盲蝽刺探木质部细胞接受过程中直接接种到葡萄藤木质部中。自 2001 年以来，人们一直在努力通过将各种抗性野生葡萄与更易感的 V. vinifera 进行经典杂交来培育抗 PD 的葡萄藤，Vitis vinifera L.。本研究使用 EPG 在 V. champinii（一种具有中等毛状体的 V. candicans/V. rupestris 天然杂种）和 V. vinifera cv. '霞多丽'（无毛状体）之间的因子实验中比较了 H. vitripennis 刺探行为，这些葡萄已经被轻轻刮除以去除毛状体或未刮除。结果表明，无论是否刮除以去除毛状体，盲蝽在霞多丽上的 X 波/X. fastidiosa 接种行为的总持续时间明显更长，而在 V. champinii 上则更短。此外，毛状体在 V. champinii 上引起更频繁的站立/行走/试探行为，一旦开始探测，其木质部就会迅速被盲蝽吸收。因此，EPG 可以检测到一种新型的葡萄对 X. fastidiosa 的抗性-除了目前大多数抗性育种的基础，即细菌感染和症状发展过程-对媒介的探测过程和细菌接种。未来的研究可以使用 EPG 来筛选这种新型抗性的葡萄藤。
