Pseudophacopteron longicaudatum (Hemiptera) induces intralaminar leaf galls on Aspidosperma tomentosum (Apocynaceae): a qualitative and quantitative structural overview

Abstract

The structural complexity of galls depends on species-specific interaction driven by the galling taxa. However, the host plant and environment stressors can impose limits on gall developmental patterns and impact the establishment of gall morphology. Herein, we employed qualitative and quantitative approaches in order to elucidate how cell divisions, elongation patterns, and tissue organization are determinant for the development of intralaminar gall morphology induced by Pseudophacopteron longicaudatum Malenovský, Burckhardt, Queiroz, Isaias & Oliveira (Hemiptera: Psylloidea: Phacopteronidae) on leaves of Aspidosperma tomentosum Mart. (Apocynaceae). In addition, we aimed to determine which anatomical process can discriminate the stages of gall development, plus, examine the histochemical and cytological profiles of the galls. The differentiated structures, mainly abaxial epidermis and spongy parenchyma, are associated with gall closure, with hyperplastic events concentrated in the young phase of the galls. Thus, epidermis and spongy parenchyma hypertrophy and are responsible for the determination of the nymphal chamber formation and gall shape. The mature galls do not differentiate into a typical nutritive cells and do not develop a histochemical gradient in their tissues. The cytological features of galls such as plastoglobules and multivesicular bodies are related to ROS scavenging mechanisms due the high oxidative stress.

As soft as silk: structural and chemical traits can help with the identification of Niphidium crassifolium (Polypodiaceae) gall inducers

“…Starch grain accumulation is expected in both Cecidomyiidae-induced galls and Hemipterainduced galls (Bronner 1992;Oliveira et al 2020;Silva et al 2019). Starch grains are metabolized by different enzymes, and the sugars are released for the feeding of the galling insect and the gall energetic metabolism (Oliveira et al 2011;Carneiro et al 2014;Bragança et al 2017).…”

Caracterização de um novo agente causal associado a manchas cloróticas em citros

“…Em análises de MET da amostra de tecido foliar do isolado CdA_10 infectado com HGSV2 foram observadas vesículas contendo estruturas arredondadas de aproximadamente 50 nm de diâmetro, de identidade ainda desconhecida, mas que poderiam ser vírions de HGSV2. Estruturas com igual aparência, chamadas corpúsculos multivesiculares, são observadas em caso de estresse celular (MARTINI et al, 2020) 2) Os genomas dos isolados brasileiros de HGSV2 possuem mais de 94% de identidade nucleotídica com o isolado de referência do Havaí, mas seu RNA3 apresenta uma organização diferente.…”