Molecular and Histologic Adaptation of Horned Gall Induced by the Aphid Schlechtendalia chinensis (Pemphigidae)

Abstract

Chinese galls are the result of hyperplasia in host plants induced by aphids. The metabolism and gene expression of these galls are modified to accommodate the aphids. Here, we highlight the molecular and histologic features of horned galls according to transcriptome and anatomical structures. In primary pathways, genes were found to be unevenly shifted and selectively expressed in the galls and leaves near the galls (LNG). Pathways for amino acid synthesis and degradation were also unevenly shifted, favoring enhanced accumulation of essential amino acids in galls for aphids. Although galls enhanced the biosynthesis of glucose, which is directly available to aphids, glucose content in the gall tissues was lower due to the feeding of aphids. Pathways of gall growth were up-regulated to provide enough space for aphids. In addition, the horned gall has specialized branched schizogenous ducts and expanded xylem in the stalk, which provide a broader feeding surface for aphids and improve the efficiency of transportation and nutrient exchange. Notably, the gene expression in the LNG showed a similar pattern to that of the galls, but on a smaller scale. We suppose the aphids manipulate galls to their advantage, and galls lessen competition by functioning as a medium between the aphids and their host plants.

A chromosome‐scale genome of Rhus chinensis Mill. provides new insights into plant–insect interaction and gallotannins biosynthesis

“…HCT is a crucial enzyme in the initial stages of lignin biosynthesis, primarily involved in the production of lignin and the extension of fiber length (Besseau et al., 2007; Lu, Kai, et al., 2021; Weng & Chapple, 2010). Histological studies have revealed that the formation and development of CG are accompanied by lignification (Hirano et al., 2020; Lu, Chen, et al., 2021). Here, we constructed a biosynthetic pathway diagram of lignin and analyzed the expression levels of multiple genes in the pathway.…”

“…Furthermore, most LAC and HCT gene family members showed identical expression patterns and were highly expressed in SG and RG (Figure 3c; Table S31). Histological investigations have demonstrated that the lignification of secondary cell walls leads to the hardening of the CG's outer epidermal cell layer (Hirano et al., 2020; Lu, Chen, et al., 2021). These lignin biosynthesis genes may contribute to the construction of CG structures.…”

Integrated Transcriptome and Metabolome Dynamic Analysis of Galls Induced by the Gall Mite Aceria pallida on Lycium barbarum Reveals the Molecular Mechanism Underlying Gall Formation and Development

“…A few genes involved in the Calvin cycle were found to be significantly upregulated in galled tissues compared with ungalled tissues. Considering that there were no stomas in the inner galled tissues, this promotion of the Calvin cycle may be attributable to the CO 2 produced during gall mite respiration inside the gall, as shown in the galls of D. vitifoliae and Schlechtendalia chinensis [ 15 , 33 ].…”

“…Phytohormones related to cell growth and cell division, such as auxins (AUXs) and cytokinins (CKs), generally increase in galls [ 11 , 12 ]. Tissues inside galls are usually rich in sugar, proteins, amino acids and other nutrients [ 13 , 14 , 15 ], and tissues outside galls are abundant in phenols, flavonoids and other secondary metabolites [ 16 , 17 , 18 , 19 ]. Meanwhile, the activity of oxidative enzymes such as superoxide dismutase (SOD), catalase (CAT), peroxidase (POD) and polyphenol oxidase (PPO) [ 20 , 21 ], and defense-related phytohormones such as salicylic acid (SA) and jasmonic acid (JA) [ 22 ], are also enhanced during gall development.…”

A study on the effect of host plants on Chinese gallnut morphogenesis

“…The sequences of the target genes were selected based on transcriptomes generated from previous studies (transcriptomes were submitted to the National Centre for Biotechnology Information Sequence Read Archive database, and can be found at the following sites: https://www.ncbi.nlm.nih.gov/bioproject/PRJNA631065 and https://www.ncbi.nlm.nih.gov/bioproject/PRJNA662477 ) [ 43 , 44 ]. Specific primers were designed using Primer-primer 6.0, and the relative quantification method was used, with the first stage leaf samples as the control and tubulin as the reference gene.…”