Comparative Transcriptional and Anatomical Analyses of Tolerant Rough Lemon and Susceptible Sweet Orange in Response to 'Candidatus Liberibacter asiaticus' Infection
Comparative Transcriptional and Anatomical Analyses of Tolerant Rough Lemon and Susceptible Sweet Orange in Response to 'Candidatus Liberibacter asiaticus' Infection
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DOI：
10.1094/mpmi-06-12-0150-r
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发表时间：
2012-11-01
影响因子：
3.5
通讯作者：
Gmitter, Frederick G., Jr.
中科院分区：
文献类型：
--
作者：
Fan, Jing;Chen, Chunxian;Gmitter, Frederick G., Jr.
虽然没有已知的遗传抗性来源，但据报道，一些柑橘类对黄龙病（HLB）具有耐受性，可能是由“亚洲候选菌”引起的。对耐受性粗柠檬（Citrus jambhiri）和易感甜橙（C. sinensis）对亚洲Ca. L. asiaticus侵染的时间序列转录分析显示，受hlb影响的粗柠檬早期基因差异表达多于甜橙，但后期基因差异表达明显减少，这可能是对亚洲Ca. L. asiaticus敏感性差异的关键因素。途径分析表明，粗柠檬和甜橙的胁迫反应具有明显的调节作用。虽然在两种感染物种中都发现了微观变化（如筛元中胼胝质沉积和韧皮部细胞崩溃），但值得注意的是，粗柠檬源叶中脉韧皮部运输活性受HLB的影响远小于甜橙。韧皮部细胞运输活动的差异也与两种植物对HLB的不同敏感性有关。该结果可能有助于鉴定粗柠檬抑制疾病发展和维持（或恢复）韧皮部运输活性的关键基因和遗传机制。这些潜在的候选基因可以通过基因工程提高柑橘对HLB的耐受性（甚至抗性）。
Although there are no known sources of genetic resistance, some Citrus spp. are reportedly tolerant to huanglongbing (HLB), presumably caused by 'Candidatus Liberibacter asiaticus'. Time-course transcriptional analysis of tolerant rough lemon (Citrus jambhiri) and susceptible sweet orange (C. sinensis) in response to 'Ca. L. asiaticus' infection showed more genes differentially expressed in HLB-affected rough lemon than sweet orange at early stages but substantially fewer at late time points, possibly a critical factor underlying differences in sensitivity to 'Ca. L. asiaticus'. Pathway analysis revealed that stress responses were distinctively modulated in rough lemon and sweet orange. Although microscopic changes (e.g., callose deposition in sieve elements and phloem cell collapse) were found in both infected species, remarkably, phloem transport activity in midribs of source leaves in rough lemon was much less affected by HLB than in sweet orange. The difference in phloem cell transport activities is also implicated in the differential sensitivity to HLB between the two species. The results potentially lead to identification of key genes and the genetic mechanism in rough lemon to restrain disease development and maintain (or recover) phloem transport activity. These potential candidate genes may be used for improving citrus tolerance (or even resistance) to HLB by genetic engineering.