文献类型： 外文期刊

作者： Bilal, Muhammad Saqib ¹ ; Paul, Gomes ¹ ; Yu, Ze ¹ ; Xu, Le ¹ ; Cheng, Tang ¹ ; Cheng, Baoping ² ; Aslam, Muhammad Naveed ³ ; Baig, Ayesha ⁴ ; Zhao, Hongwei ¹ ;

作者机构： 1.Nanjing Agr Univ, Coll Plant Protect, Key Lab Plant Immun, Nanjing 210095, Peoples R China

2.Guangdong Acad Agr Sci, Key Lab Green Prevent & Control Fruits & Vegetable, Guangdong Prov Key Lab High Technol Plant Protect, Inst Plant Protect,Minist Agr & Rural Affairs, Guangzhou 510640, Peoples R China

3.Islamia Univ Bahawalpur, Fac Agr & Environm, Dept Plant Pathol, Bahawalpur 63100, Pakistan

4.COMSATS Univ Islamabad, Dept Biotechnol, Abbottabad Campus, Abbottabad 22010, Pakistan

关键词： lemon; Shatangju; starch accumulation; antioxidant enzymes; DE-miRNA; csi-miR399; csi-miR166

期刊名称：PLANTS-BASEL （ 影响因子：4.0； 五年影响因子：4.4 ）

ISSN： 2223-7747

年卷期： 2024 年 13 卷 11 期

页码：

收录情况： SCI

摘要： Citrus Huanglongbing (HLB), caused by the phloem-inhibiting bacterium Candidatus Liberibacter asiaticus (CLas), is the most devastating citrus disease, intimidating citrus production worldwide. Although commercially cultivated citrus cultivars are vulnerable to CLas infection, HLB-tolerant attributes have, however, been observed in certain citrus varieties, suggesting a possible pathway for identifying innate defense regulators that mitigate HLB. By adopting transcriptome and small RNAome analysis, the current study compares the responses of HLB-tolerant lemon (Citrus limon L.) with HLB-susceptible Shatangju mandarin (Citrus reticulata Blanco cv. Shatangju) against CLas infection. Transcriptome analysis revealed significant differences in gene expression between lemon and Shatangju. A total of 1751 and 3076 significantly differentially expressed genes were identified in Shatangju and lemon, respectively. Specifically, CLas infected lemon tissues demonstrated higher expressions of genes involved in antioxidant enzyme activity, protein phosphorylation, carbohydrate, cell wall, and lipid metabolism than Shatangju. Wet-lab experiments further validated these findings, demonstrating increased antioxidant enzyme activity in lemon: APX (35%), SOD (30%), and CAT (64%) than Shatangju. Conversely, Shatangju plants exhibited higher levels of oxidative stress markers like H2O2 (44.5%) and MDA content (65.2%), alongside pronounced ion leakage (11.85%), than lemon. Moreover, microscopic investigations revealed that CLas infected Shatangju phloem exhibits significantly more starch and callose accumulation than lemon. Furthermore, comparative sRNA profiles revealed the potential defensive regulators for HLB tolerance. In Shatangju, increased expression of csi-miR166 suppresses the expression of disease-resistant proteins, leading to inadequate defense against CLas. Conversely, reduced expression of csi-miR166 in lemon plants enables them to combat HLB by activating disease-resistance proteins. The above findings indicate that when infected with CLas, lemon exhibits stronger antioxidative activity and higher expression of disease-resistant genes, contributing to its enhanced tolerance to HLB. In contrast, Shatangju shows lower antioxidative activity, reduced expression of disease-resistant genes, significant ion leakage, and extensive callose deposition, possibly related to damage to plant cell structure and blockage of phloem sieve tubes, thereby promoting the development of HLB symptoms.