In response to insect attack,plants use intricate signaling pathways,including phytohormones,such as jasmonate(JA),ethylene(ET),and salicylic acid(SA),to activate defenses.Maize(Zea mays)is one of the most important staple food crops around the world.Previous studies have shown that the JA and ET signaling play important roles in maize defense against insects,but little is known about whether and how SA regulates maize resistance to insect herbivores.In this study,we ectopically expressed the NahG(salicylate hydroxylase)gene in maize plants(NahG maize)to block the accumulation of SA.It was found that compared with the wild-type(WT)maize,the NahG maize exhibited decreased resistance to the generalist insects Spodoptera litura and Spodoptera frugiperda and the specialist Mythimna separata,and the compromised resistance in the NahG maize was associated with decreased levels of defensive me-tabolites benzoxazinoids(Bxs)and chlorogenic acid(CA).Quantification of simulated S.litura feeding-induced JA,JA-isoleucine conjugate(JA-Ile),and ET in the WT and NahG maize indicated that SA does not regulate JA or JA-Ile,but positively controls ET.We provide evidence suggesting that the SA pathway does not crosstalk with the JA or the ET signaling in regulating the accumulation of Bxs and CA.Tran-scriptome analysis revealed that the bHLH,ERF,and WRKY transcription factors might be involved in SA-regulated defenses.This study uncovers a novel and important phytohormone pathway in maize defense against lepidopterous larvae.

七连屿是西沙群岛东北面的一个珊瑚礁群岛,生物多样性极高,近年来由于受到了人类扰动影响,鱼类资源出现明显衰退.为探究这一衰退演变特征并更好地保护和管理七连屿珊瑚礁鱼类资源,我们于2018-2023年采用潜水捕捞、渔捞日志记录、水下视频拍摄以及环境DNA分析等方法,并结合近年这一海域的研究资料,对其鱼类种类组成的现状进行分析.结果如下:2017年至今,七连屿共发现珊瑚礁鱼类412种,隶属于2纲16目60科168属,其中鲈形目鱼类最多,为320种,科水平隆头鱼科种类最多,有47种.七连屿以小型鱼类为多;食性方面以肉食性鱼类为多.2021-2023年大中型鱼类比例及肉食性鱼类比例较2017-2020年出现下降,同时小型鱼类和植食性鱼类比例却出现显著上升.两时间段肉食性鱼类相似性较低,为不相似;植食性鱼类相似性较高,为中等相似;小型鱼类相似性较低,为不相似,大型鱼类也为不相似.优势种中大型鱼类和小型鱼类的种类数显著低于稀有鱼类,肉食性鱼类的种类数也显著低于稀有鱼类,而植食性鱼类的种类数则显著高于稀有鱼类.两时间段的鱼类平均分类差异指数(Delta+)和变异分类差异指数(Lambda+)呈下降趋势.以上表明七连屿珊瑚礁鱼类受到了过度捕捞和生境退化的双重影响,鱼类物种发生了显著的更替.研究为今后预测七连屿珊瑚礁鱼类物种演替趋势提供了基础数据,为西沙珊瑚礁生态系统保护和修复提供了参考.

Jasmonates(JAs),a class of lipid-derived stress hormones,play a crucial role across an array of plant phys-iological processes and stress responses.Although JA signaling is thought to rely predominantly on the degradation of specific JAZ proteins by SCFCOI1,it remains unclear whether other pathways are involved in the regulation of JAZ protein stability.Here,we report that PUB22,a plant U-box type E3 ubiquitin ligase,plays a critical role in the regulation of plant resistance against Helicoverpa armigera and other JA re-sponses in tomato.Whereas COI1 physically interacts with JAZ1/2/5/7,PUB22 physically interacts with JAZ1/3/4/6.PUB22 ubiquitinates JAZ4 to promote its degradation via the 26S proteasome pathway.Impor-tantly,we observed that pub22 mutants showreduced resistance to H.armigera,whereasjaz4 single mu-tants and jaz1 jaz3 jaz4 jaz6 quadruple mutants have enhanced resistance.The hypersensitivity of pub22 mutants to herbivores could be partially rescued by JAZ4 mutation.Moreover,we found that expression of PUB22 can be transcriptionally activated by MYC2,thus forming a positive feedback circuit in JA signaling.We noticed that the PUB22-JAZ4 module also regulates other JA responses,including defense against B.cinerea,inhibition of root elongation,and anthocyanin accumulation.Taken together,these re-sults indicate that PUB22 plays a crucial role in plant growth and defense responses,together with COI1-regulated JA signaling,by targeting specific JAZs.

Lignin emerged around 450 million years ago in early tracheo-phytes and played a pivotal role in the colonization of terrestrial ecosystems by plants.This aromatic biopolymer provides mechanical strength to supportive tissues and hydrophobicity to water-transporting vasculature and acts as a physical barrier against herbivores and pathogens(Renault et al.,2019).

植食性昆虫与寄主植物在长期协同进化的历程中,两者逐渐演化出丰富多样的防御与反防御机制,其中在植食性昆虫适应植物防御的过程中,唾液腺分泌物起到关键性的作用.本研究从宏观与微观两个层面,揭示植食性昆虫如何利用唾液腺以适应寄主植物防御的作用机理.回顾了昆虫唾液腺分泌物通过干预植物气孔的动态变化、适应植物细胞壁、降解植物防御性化合物等方式调控寄主植物防御的研究进展,探讨了昆虫唾液效应因子以干扰植物早期免疫信号通路、调节植物激素信号通路、与植物免疫蛋白互作等形式应对植物防御反应的内在分子机制.同时,本文依据CRISPR/Cas9、植物介导的RNAi、纳米材料介导的RNAi等新技术的发展,对基于昆虫效应因子开发的虫害防控技术的发展空间进行分析,以期为作物抗性的提高以及害虫综合治理能力的提升提供理论依据与实践指导.

高阶作用通常指一个物种对另外两个物种之间相互作用强度的影响,对物种共存、群落构建及生物多样性具有重要影响.在集合种群水平上考虑了植食动物对动植物传粉关系造成的高阶作用,以及植食动物对传粉者的间接作用.通过分析基本生态过程,建立植物-传粉者-植食动物的集合群落模型,模型清楚地展示高阶作用和间接作用,可以用来研究它们对集合群落稳定性和续存的影响.结果表明:(1)互惠关系在集合群落尺度上会引起双稳态现象,说明了群落动态对初始条件的依赖性;(2)正高阶作用能够扩大集合群落双稳态的参数范围,负高阶作用和间接作用缩小它的参数范围,但都不会从本质上改变双稳态现象;(3)正高阶作用能够降低集合群落的灭绝阈值,增加集合群落稳定时的占有率,有利于集合群落续存,而负高阶作用和间接作用不利于续存.研究结果说明高阶和间接作用对调节多物种系统动态和物种共存具有重要作用.

多样的花冠形态具有保护花内性器官、吸引传粉者等多种作用,管状花的出现被认为是花瓣演化的一个变革性事件.自达尔文以来,学者们试图回答的一个经典问题是:长花冠管的演化是否由传粉者口器与花冠管之间长度的"军备竞赛"引起?人们已在长花冠管的多个类群中开展了实验,试图寻找交互选择引起的动植物之间协同演化的证据.本文总结了影响植物花冠管长演化的生物因素和非生物因素,探讨了传粉者、盗蜜者、植食者、光照、水分等因素在花冠管长演化中扮演的角色,重点梳理了传粉者介导花冠管长演化的4个潜在路径,以期为进一步探究植物花冠管长度的演化提供新的思路和方向.

揭示中国沙棘(Hippophiae rhamnoides subsp.sinensis Rousi)根尖在形态、水力结构和非结构性碳水化合物(NSC)浓度对环境条件及外界干扰的响应有利于全面了解中国沙棘对环境条件在水分利用和碳素分配上的适应能力和适应策略.以山西省交城县野生沙棘林为研究对象,选取坡下部正常、坡下部动物啃食、坡上部正常和坡上部动物啃食4种类型沙棘,分析沙棘根尖形态、水力结构、非结构性碳水化合物(NSC)的响应.结果显示:与坡下部相比,在坡上部相对缺水的环境下中国沙棘根尖比根长显著增加,根尖的平均长度、直径、皮层厚度和中柱直径没有显著性变化,根尖导管直径降低、导管密度增加;根尖的比导水率正常和动物啃食分别降低18.12％和20.6％,水力脆弱性指数分别降低45.40％和48.5％,NSC含量没有显著性变化.动物啃食导致根尖比根长降低、平均直径增加、皮层厚度和中柱直径增加,导管直径降低、导管密度增加,坡上和坡下动物啃食导致比导水率降低71.14％和70.25％,水力脆弱性指数降低23.95％和19.41％.以上结果表明:坡上部较差的水分条件使中国沙棘根尖有更大的吸收面积,水分输导效率小幅降低,水力安全性较大程度提升;动物啃食导致根尖增粗、导水率较大程度降低、水力安全性小幅提升.坡位和动物啃食均未导致根尖NSC含量降低,动物啃食在坡上部相对缺水的环境中根尖响应程度更大.这表明中国沙棘根尖对坡位和动物啃食的响应有助于对两种影响因素的适应,动物啃食对根尖吸收和运输功能的影响程度更大.

Soil microbial mutualists of plants,including mycorrhizal fungi,non-mycorrhizal fungi and plant growth promoting rhizobacteria,have been typically characterized for increasing nutrient acquisition and plant growth.More recently,soil microbes have also been shown to increase direct plant defense against above-and belowground herbivores.Plants,however,do not only rely on direct defenses when attacked,but they can also recruit pest antagonists such as predators and parasitoids,both above and belowground,mainly via the release of volatile organic compounds (i.e.,indirect defenses).In this review,we illustrate the main features and effects of soil microbial mutualists of plants on plant indirect defenses and discuss possible applications within the framework of sustainable crop protection against root-and shoot-feeding arthropod pests.We indicate the main knowledge gaps and the future challenges to be addressed in the study and application of these multifaceted interactions.

Interactions between plants and phytophagous insects play an important part in shaping the biochemical composition of plants.Reciprocally plant metabolites can influence major life history traits in these insects and largely contribute to their fitness.Plant rhizospheric microorganisms are an important biotic factor modulating plant metabolites and adaptation to stress.While plant-insects or plant-microorganisms interactions and their consequences on the plant metabolite signature are well-documented,the impact of soil microbial communities on plant defenses against phytophagous insects remains poorly known.In this study,we used oilseed rape (Brassica napus) and the cabbage root fly (Delia radicum) as biological models to tackle this question.Even though D.radicum is a belowground herbivore as a larva,its adult life history traits depend on aboveground signals.We therefore tested whether soil microbial diversity influenced emergence rate and fitness but also fly oviposition behavior,and tried to link possible effects to modifications in leaf and root metabolites.Through a removal-recolonization experiment,3 soil microbial modalities ("high," "medium," "low") were established and assessed through amplicon sequencing of 16S and 18S ribosomal RNA genes.The "medium" modality in the rhizosphere significantly improved insect development traits.Plant-microorganism interactions were marginally associated to modulations of root metabolites profiles,which could partly explain these results.We highlighted the potential role of plant-microbial interaction in plant defenses against Delia radicum.Rhizospheric microbial communities must be taken into account when analyzing plant defenses against herbivores,being either below or aboveground.