Recently, researchers from Institute of Vegetables and Flowers (IVF) of Chinese Academy of Agricultural Sciences (CAAS), in collaboration with Institute of Biology of University of  Neuchâtel etc. reported their research results in a paper entitled “Functional divergence of plant-derived thaumatin-like protein genes in two closely related whitefly species” published in the journal Advanced Science.

The greenhouse whitefly, Trialeurodes vaporariorum, and the sweet potato whitefly, Bemisia tabaci, two of the most widespread and agriculturally important whitefly pests in the family Aleyrodidae. They cause extensive damage to various crops worldwide through phloem feeding and in particular by transmitting plant viruses and excreting honeydew. The two closely related whiteflies are highly similar in morphology, with primarily only slight differences in the posture of the adult wings and the shape of the fourth instar nymphs. However, they exhibit clear differences in various aspects of their biology and ecology, including host plant range, insecticide resistance, behavior, and the ability and specificity of virus transmission.

Horizontal gene transfer (HGT), which refers to the stable inheritance of genetic material between unrelated species, has been extensively documented with functional conservation of transferred genes retaining ancestral characteristics. However, the evolutionary trajectory of horizontally transferred genes remains enigmatic - particularly whether they may undergo accelerated evolution and even functional divergence between closely related species remains an open question in evolutionary biology.

Researchers have identified a plant-derived thaumatin-like protein (TLP) gene in the genomes of T. vaporariorum and B. tabaci. TLP serves antifungal functions in N. tabacum. Originally, T. vaporariorum and B. tabaci adapt in parallel to similar environments. Over time, T. vaporariorum retains the antifungal function of the TLP gene, while the TLP gene in the closely related species B. tabaci undergoes subfunctionalization and assumes the role as an effector to suppress the JA signaling pathway in host plants. The horizontally transferred TLP gene, which exhibits functional "polymorphism" akin to the three-headed, six-armed deity Nezha in Chinese mythology - where a single ancestral entity diverges into specialized "avatars"

Figure 1. The plant-derived TLP genes functionally diverged between T. vaporariorum and B. tabaci.

The research was supported by the National Key R & D Program of China, the National Natural Science Foundation of China, the Beijing Key Laboratory for Pest Control and Sustainable Cultivation of Vegetables, the Science and Technology Innovation Program of the Chinese Academy of Agricultural Sciences and the European Research Council Advanced Grant.

More information can be found through the link: https://advanced.onlinelibrary.wiley.com/doi/10.1002/advs.202502193

By Zhaojiang Guo (guozhaojiang@caas.cn)