Schultz Jack C, Body Mélanie J A, Edger Patrick P, Witiak Sarah Melissa, Appel Heidi M
Department of Biology and Biochemistry, University of Houston, Houston, TX, 77004, USA.
Department of Horticulture, Michigan State University, East Lansing, MI, 48824, USA.
New Phytol. 2025 Aug;247(4):1712-1726. doi: 10.1111/nph.70241. Epub 2025 Jun 20.
Galls are structures formed by plants in response to stimuli by parasitic insects. Because galls require altered gene expression to change cell fates, their initiation requires pluripotent or 'reactive' cells. We used RNA sequencing to test three hypotheses about potential sources of pluripotency in the leaf gall formed by grape phylloxera (Daktulosphaira vitifoliae). We postulated that the insect might express ectopically genes regulating apical meristem pluripotency, exploit preexisting meristems, or induce callus cells de novo. We found that phylloxera exploits preexisting cambial and leaf meristems and promotes callus formation. Pluripotency gene expression increases as leaf cells differentiate, extending gall induction opportunity. Auxin regulates pluripotency gene expression. We found evidence of enhanced auxin synthesis and signaling in the gall and of cytokinin (CK) accumulation and signaling. However, we found no evidence for CK synthesis by the plant. Our results support the view that cellular pluripotency is central to gall development and point to sources of pluripotency in galls of an economically important insect. Results also implicate auxin and CK signaling as a means by which pluripotency is established and maintained in the developing gall.
虫瘿是植物对寄生昆虫刺激作出反应而形成的结构。由于虫瘿需要改变基因表达来改变细胞命运，其起始需要多能性或“反应性”细胞。我们使用RNA测序来检验关于葡萄根瘤蚜（Daktulosphaira vitifoliae）形成的叶瘿中多能性潜在来源的三个假设。我们推测昆虫可能异位表达调节顶端分生组织多能性的基因，利用已有的分生组织，或从头诱导愈伤组织细胞。我们发现葡萄根瘤蚜利用已有的形成层和叶分生组织并促进愈伤组织形成。随着叶细胞分化，多能性基因表达增加，从而延长了虫瘿诱导机会。生长素调节多能性基因表达。我们发现虫瘿中有生长素合成和信号增强以及细胞分裂素（CK）积累和信号的证据。然而，我们没有发现植物合成CK的证据。我们的结果支持细胞多能性是虫瘿发育核心的观点，并指出了一种经济上重要昆虫的虫瘿中多能性的来源。结果还表明生长素和CK信号是在发育中的虫瘿中建立和维持多能性的一种方式。
