Biology subjects

Li, J.-M.

Publications and source records attributed to Li, J.-M..

6 recordsLinked to original sources

bioRxiv2026

Sex-determination cascade orchestrates male-male pheromone synthesis in the bean bug

Volatile pheromones are vital for insect intraspecific communication, yet the genetic basis of homosexual recognition remains elusive. In the bean bug Riptortus pedestris, we show that two previously identified aggregation pheromone components, (E)-2-hexenyl-(Z)-3-hexenoate (E2HZ3H) and (E)-2-hexenyl-(E)-2-hexenoate (E2HE2H), serve as key chemosensory cues for male-male recognition during mate selection. Their biosynthesis is governed by the sex-determination cascade Rpfmd-Rpdsx. The male-specific isoform Rpdsx_M promotes pheromone production in males and induces ectopic synthesis in females upon knockdown of the feminizing switch gene Rpfmd. Knockdown of Rpdsx_M in males abolishes both compounds, prompting wild-type males to court them as if they were females. Metathoracic gland cells act as the production hub. Behaviourally, E2HZ3H or E2HE2H disrupt mating when applied to females: males avoid such females. E2HZ3H reduces female mobility in the presence of the male-derived primary aggregation pheromone tetradecyl isobutyrate (14:iBu), whereas E2HE2H shows no obvious such effect. These differential effects ensure mating accuracy. The discovery of volatile pheromones functioning in male-male recognition and of their synthesis being governed by the sex-determination cascade updates our understanding of mating accuracy in insect chemical communication.

animal behavior and cognition↗

bioRxiv2025

Herbivorous insects independently evolved salivary effectors to regulate plant immunity by destabilizing the malectin-LRR RLP NtRLP4

Plants utilize on receptor-like proteins and receptor-like kinases (RLPs/RLKs) to perceive and respond to a wide variety of invading pathogens and insect herbivores. While the strategies employed by microbial pathogens to suppress plant immunity have been well characterized, it remains unclear how herbivorous insects counteract receptor-mediated defenses. Here, we show that salivary effectors evolve independently in whiteflies and planthoppers to dampen RLP4-mediated plant immunity. RLP4, as a leucine-rich repeat RLP (LRR-RLP), confers plant resistance against herbivorous insects by forming the RLP4/SOBIR1 complexes. In the whitefly Bemisia tabaci, BtRDP, the Aleyrodidae-specific salivary sheath protein, interacts with RLP4 from multiple plant species and promotes its ubiquitin-dependent degradation. Overexpression of NtRLP4 in transgenic plants exerts a detrimental effect on B. tabaci by exploiting the crosstalk between the salicylic acid (SA) and jasmonic acid (JA) pathways. Conversely, overexpression of BtRDP or silencing of NtRLP4 effectively alleviates such negative effects. In planthopper Nilaparvata lugens, the Delphacidae-restricted salivary protein NlSP104 also targets and promotes the degradation of OsRLP4 from rice plants. These findings reveal convergent evolution of salivary proteins in insects, and underscore the complex interactions between plants and herbivorous insects.

molecular biology↗

bioRxiv2024

Identification and characterization of vasoactive intestinal peptide receptor antagonists with high-affinity and potent anti-leukemia activity

Vasoactive intestinal peptide (VIP) is a neuropeptide involved in tumor growth and immune modulating functions. Previous research indicated that a VIP antagonist (VIPhyb) enhances T-cell activation and induces T-cell-dependent anti-leukemic activity in mice. We created a combinatorial library of VIPhyb C-terminal sequence variations to develop a more potent VIP-receptor (VIP-R) antagonist, hypothesizing that specific amino acid substitutions would improve receptor binding and plasma stability. In silico screening analyses identified sequences with improved docking scores predicting increased binding affinity to human VIP receptors VPAC1 and VPAC2. Fifteen peptides were synthesized and tested for their ability to potentiate activation of purified mouse and human T cells and enhance T cell-dependent anti-leukemia responses in murine models of acute myeloid leukemia. Treating C57Bl/6 mice engrafted with a C1498 myeloid leukemia cell line with daily subcutaneous injections of VIP-R antagonist peptides induced T cell activation resulting in specific anti-leukemia responses. Strikingly, the predicted binding affinity of the VIP-R antagonists to VIP receptors correlated positively with their ability to augment mouse T-cell proliferation and anti-leukemia activity. ANT308 and ANT195 emerged as top candidates due to their high predicted VIP-R binding, low EC50 for in vitro T cell activation, and potent anti-leukemia activities. ANT308 decreased CREB phosphorylation, a downstream signaling pathway of the VIP receptor, and stimulated granzyme B and perforin expression in CD8+ T cells from AML patients. Combining in silico modeling, in vitro T cell activation properties, and in vivo anti-leukemia activity has identified promising VIP-R antagonist candidates for further development as novel immunotherapies for AML, especially for patients with relapsed disease.

immunology↗

bioRxiv2024

Brochosomes as an antireflective camouflage coating for leafhoppers

In nature, insects face immense predation pressure, where visual cues play a vital role in predators locating them. To counter this threat, insects employ a variety of nano- and microstructures on their cuticular layer to manipulate and interact with light, enhancing anti-reflective properties and providing camouflage or reducing detectability by predators. Leafhoppers have a unique extra-cuticular coating called brochosome, yet its anti-reflective functions and protein composition remain unclear. Our study demonstrates strong anti-reflective properties of brochosomes, effectively reducing reflectance on the cuticle surface, especially in the ultraviolet spectrum, to improve evasion from visual predators. Furthermore, we identify four novel structural proteins of the brochosome (BSM) for the first time. Inhibiting their synthesis by RNAi alters brochosome morphology, impacting the optical properties of the cuticle surface. Evolutionary origin analysis of BSM suggests that brochosomes likely originated from a process involving duplication-divergence. Our study reveals that leafhoppers employ a unique camouflage strategy by secreting brochosomes as anti-reflection nano-coatings, enabling them to evade natural predators and contributing to their evolutionary success.

ecology↗

bioRxiv2023

Diversity and adaptability of RNA viruses in rice planthopper, Laodelphax striatellus

Although a large number of insect-specific viruses (ISVs) have recently been discovered from hematophagous insect, studies on ISV diversity and their association with phytophagous insect hosts were still insufficient. A systematic RNA virome investigation was performed for an important plant virus vector, small brown planthopper (SBPH), Laodelphax striatellus. A total number of 22 RNA viruses (including 17 novel viruses) belonging to various families were successfully identified and characterized. Subsequent analysis indicated that the overall RNA virus transcripts per million (TPM) in SBPH was relatively consistent throughout various different developmental stages of the insects, although the titers of individual viruses differ among different insect tissues, suggesting a delicate balance between ISVs and insect hosts. Moreover, analysis of virus-derived small interfering RNA (siRNA) demonstrated that siRNA mediated antiviral immune response of SBPH was activated in response to the replication of the discovered RNA viruses. Additionally, evaluation for potential cross-species ability of SBPH-ISVs showed that certain SBPH ISVs could successfully infect and replicate in another two rice planthoppers, the brown planthopper and the white-backed planthopper, through microinjection. In conclusion, the RNA virome and their adaptability in SBPH revealed in this study will contribute to a better understanding of the intimate relationship between ISVs and the host insects.

microbiology↗

bioRxiv2019

EphB6 regulates social behavior through gut microbiota-mediated vitamin B6 metabolism and excitation/inhibition balance of medial prefrontal cortex in mice

Autism spectrum disorder (ASD) is a developmental disorder with no effective pharmacological treatments so far. Gut microbiota has been suggested to contribute to autistic symptoms. However, the key genes and the mechanisms linking gut microbiota and brain dysfunctions in ASD are still unclear. Here, we found deletion of EphB6, an ASD-associated candidate gene, induced dysregulated gut microbiota and autism-like behavior in mice. More importantly, transplanting fecal microbiota from EphB6-deficient mice resulted in disturbed gut microbiota and autism-like behavior in antibiotics-treated C57BL/6J mice. Meanwhile, transplanting fecal microbiota from wild-type mice ameliorated disturbed gut microbiota and autism-like behavior in mice with deletion of EphB6. At the metabolic levels, dysregulated gut microbiota led to vitamin B6 and dopamine defects in EphB6-deficient mice. At the cellular levels, excitation/inhibition (E/I) imbalance in medial prefrontal cortex was induced by gut microbiota-mediated defects of vitamin B6 metabolism in EphB6-deficient mice. Our study uncovers a key role for EphB6 in regulation of social behavior by gut microbiota-mediated vitamin B6 metabolism, dopamine synthesis and E/I balance, suggesting a new strategy for treatment of ASD patients.

neuroscience↗