Universidade Federal do Rio de Janeiro, Instituto de Biologia, Departamento de Botânica, Av. Carlos Chagas Filho, 353, A1-104, Cidade Universitária, 21941-902, Rio de Janeiro, RJ, Brazil.
Universidade Federal do Rio Grande do Sul, Instituto de Biociências, Departamento de Zoologia, Av. Bento Gonçalves 9500, Campus do Vale, 91501-970, Porto Alegre, RS, Brazil.
Am J Bot. 2022 Feb;109(2):209-225. doi: 10.1002/ajb2.1798. Epub 2022 Feb 7.
Gall-inducing organisms change the development of their host plant organs, resulting in ontogenetic patterns not observed in the non-galled plants. Distinct taxa induce galls on Schinus spp., manipulating meristematic patterns in the host plant in distinct ways. Here we report ontogenetic novelties induced in the lateral buds of S. engleri by Eucecidoses minutanus, a Cecidosidae, whose galls have been poorly understood.
The anatomy, histochemistry, and histometry of galls in distinct phases of development, non-galled buds, and stems of Schinus engleri were analyzed in parallel with the instars of E. minutanus to detail the morphogenetic changes in the host with each larval stage.
Ontogenetic phases of the galls were intricately associated with larval development. First and second-instar larvae induced pericycle and pith cells to dedifferentiate into the gall inner meristem, where hyperplasia and cell hypertrophy characterized the growth and development phase of the gall. The innermost layers were lipid-rich nutritive cells that lined the larval chamber. Additional vascular bundle rows were produced in young galls. Third and fourth instar-larvae were associated with the gall maturation phase: centripetal lignification of the outer parenchyma cell layers, epidermal stratification, and activation of a cambium-like meristem (CLM). The CLM activity resulted in new layers of nutritive cells that differentiated inward as the first layers of nutritive cells were consumed by E. minutanus larvae, and, also, in more parenchyma cell layers that formed outward. All tissues between the innermost layer of nutritive tissue that surround the gall chamber and the outermost layer of the dermal system that externally covers the gall form the gall wall, and increased in thickness until the end of gall maturation.
E. minutanus induces a structurally complex globoid stem gall, modifying all host plant tissues and stimulating a novel meristematic pattern in S. engleri. The gall developmental stages are each related to specific gall-inducing instars, as gall development progresses according to the development of E. minutanus.
诱导组织的生物体改变其宿主植物器官的发育，导致在非肿胀植物中观察不到的个体发生模式。不同的分类群以不同的方式诱导 Schinus 属植物的虫瘿，从而操纵宿主植物的分生组织模式。在这里，我们报告了由 Cecidosidae 的 Eucecidoses minutanus 诱导的 S. engleri 侧芽的个体发生新颖性，其虫瘿的了解甚少。
通过与 E. minutanus 的龄期相平行，分析了处于不同发育阶段、非肿胀芽和 S. engleri 茎的虫瘿的解剖结构、组织化学和组织计量学，以详细描述宿主与每个幼虫阶段相关的形态发生变化。
虫瘿的个体发生阶段与幼虫发育密切相关。第一和第二龄幼虫诱导周皮和髓细胞去分化为瘿内分生组织，其中增生和细胞肥大是瘿生长和发育阶段的特征。最内层是富含脂质的营养细胞，排列在幼虫室周围。在年轻的瘿中还产生了额外的维管束列。第三和第四龄幼虫与瘿成熟阶段相关：外薄壁细胞层的向心木质化、表皮分层和激活类似于形成层的分生组织 (CLM)。CLM 活性导致新的营养细胞层向内分化，因为第一营养细胞层被 E. minutanus 幼虫消耗，并且也向外形成更多的薄壁细胞层。围绕瘿室的最内层营养组织和外部覆盖瘿的真皮系统的最外层之间的所有组织形成瘿壁，并在瘿成熟结束前增加厚度。
E. minutanus 诱导结构复杂的球形茎瘿，改变宿主植物的所有组织，并刺激 S. engleri 中一种新的分生组织模式。瘿的发育阶段与特定的诱导龄期相关，因为随着 E. minutanus 的发育，瘿的发育进展。
