【摘要】 植物磺肽素(phytosulfokine, PSK)是一类重要的植物肽类激素，在植物抗病防御过程中发挥重要作用。为系统解析PSKs基因家族在西瓜(Citrullus lanatus)抗病防御反应中的功能，本研究利用生物信息学方法，对西瓜PSKs基因进行全基因组鉴定和生物信息学分析，并系统分析其在果实不同发育及其枯萎病菌(Fusarium oxysporum f. sp. niveum)侵染下的表达模式。结果表明，西瓜基因组中可鉴定到4个ClPSKs基因(Cla97C01G016930, Cla97C08G160340, Cla97C10G193065和Cla97C10G202430)，这些基因分布在3条染色体上。ClPSKs编码蛋白的分子量在9.276～11.491 kD之间，均为酸性、不稳定蛋白，且所有蛋白均含有PSK家族保守基序。系统进化分析表明，西瓜ClPSKs与拟南芥(Arabidopsis thaliana) AtPSKs聚为一类，表明其在进化过程中具有高度保守性。启动子顺式作用元件分析表明，ClPSKs基因启动子区富含胁迫响应元件和植物激素响应元件，为其参与植物胁迫响应提供了分子基础。qPCR分析显示，ClPSKs基因在西瓜不同组织中呈现差异表达特征，其中叶片中表达量最高，根系次之。Cla97C01G016930、Cla97C08G160340和Cla97C10G193065在西瓜果实授粉后10 d表达量最高，提示这些基因可能参与调控西瓜果实早期发育进程。枯萎病菌侵染显著诱导了ClPSKs基因的表达。其中，Cla97C01G016930、Cla97C08G160340和Cla97C10G193065在侵染后12 h达到表达峰值，而Cla97C10G202430表现为持续上调表达模式，表明不同ClPSKs成员可能通过时空调控参与西瓜抗病防御反应。本研究为深入解析ClPSKs基因在西瓜抗病防御反应中的功能提供了科学参考。更多还原

【Abstract】 Phytosulfokine(PSK), a class of essential plant peptide hormones, plays critical roles in plant disease resistance and defense responses. To systematically dissect the functions of the PSK gene family in watermelon(Citrullus lanatus) defense responses, a genome-wide identification and bioinformatics analysis of ClPSKs were performed, followed by expression profile analysis during fruit development and upon Fusarium oxysporum f. sp. niveum infection. The results showed that 4 ClPSKs(Cla97C01G016930, Cla97C08G160340,Cla97C10G193065 and Cla97C10G202430) were identified in the watermelon genome, distributed across3 watermelon chromosomes. The molecular weight of ClPSKs-encoded proteins ranged from 9.276 to11.491 kD. All ClPSKs were acidic and unstable proteins, and they all contained PSK family conserved motifs. The phylogenetic tree analysis showed that watermelon ClPSKs clustered with AtPSKs from Arabidopsis thaliana, indicating high evolutionary conservation. Promoter cis-acting element analysis revealed that the stress responsive cis-elements and the plant hormone responsive cis-elements were enriched in the promoter sequence of watermelon PSKs gene, which providing a molecular basis for ClPSKs involvement in stress responses. Expression analysis showed that ClPSKs exhibited tissue-differential expression, with the highest levels in leaf tissues, followed by roots. Cla97C01G016930, Cla97C08G160340 and Cla97C10G193065 exhibited the highest expression levels at 10 d after pollination of watermelon fruit,indicating that these genes played a role in the early stage of watermelon fruit growth and development.Fusarium oxysporum infection significantly induced the expression of ClPSKs genes. Cla97C01G016930,Cla97C08G160340, and Cla97C10G193065 had the highest expression levels at 12 h after F. oxysporum f. sp.niveum infection, while Cla97C10G202430 showed continuous upregulation, indicating distinct spatiotemporal roles of ClPSKs in disease defense. This study provides scientific references for further understanding the role of ClPSKs in watermelon disease resistance and defense responses.更多还原