Combinations of a host resistance gene and the CI gene of turnip mosaic virus differentially regulate symptom expression in Brassica rapa cultivars
Combinations of a host resistance gene and the CI gene of turnip mosaic virus differentially regulate symptom expression in Brassica rapa cultivars
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DOI：
10.1007/s00705-011-1036-6
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发表时间：
2011-09-01
影响因子：
2.7
通讯作者：
Masuta, Chikara
中科院分区：
文献类型：
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作者：
Fujiwara, Ayaka;Inukai, Tsuyoshi;Masuta, Chikara
在油菜和芜菁花叶病毒（TuMV）的致病系统中，易感植物表达的症状类型是由宿主品种和病毒株之间的基因组合决定的。在这项研究中，我们发现抗性反应和症状如系统性致死坏死、叶片畸形和花叶是不同的，这取决于一个宿主位点或两个紧密相连的宿主位点与病毒CI基因的基因型组合。TuMV-UK1对部分rapa亚种引起全身坏死。该基因与R6染色体上的抗tumv基因Rnt1-1等位或密切相关。Rnt1-2对rnt1-3不完全隐性，不引起任何坏死反应。基因型rnt1-2/rnt1-3导致严重畸形叶片沿叶脉轻度坏死。一个自发突变体TuMV-UK1 (UK1m)，在CI中氨基酸替换为V1827E，打破了Rnt1-1抗性，改变了rnt1-2诱导的全身坏死和叶片畸形。UK1的CI蛋白中的这个氨基酸也与严重的花叶和叶片发育异常有关，可能与未知的宿主因素相互作用。为明确Rnt1-1与R6染色体上TuMV-UK1抗性基因TuRB01b之间的关系，将携带TuRB01b的rapa品种Tropical Delight与UK1m或CI V1827E突变的传染性UK1克隆接种。由于Tropical Delight对这两种突变体都有抗性，因此Rnt1-1可能与TuRB01b不同。
In the pathosystem of Brassica rapa and turnip mosaic virus (TuMV), the type of symptoms expressed by susceptible plants are determined by the gene combinations between the host cultivar and virus strain. In this study, we found that the resistance reaction and symptoms such as systemic lethal necrosis, leaf malformation and mosaic were differentially determined, depending on the combinations of the genotypes for a host locus or two closely linked host loci and the viral CI gene. Systemic necrosis caused by TuMV-UK1 on some B. rapa subsp. pekinensis cultivars is induced in conjunction with a recessive gene, rnt1-2 (resistance and necrosis to tumv 1-2), which is allelic or closely linked to TuMV resistance gene Rnt1-1 on chromosome R6. rnt1-2 is incompletely recessive to rnt1-3, which does not cause any necrotic responses. The genotype rnt1-2/rnt1-3 caused a mild necrosis along leaf veins of severely malformed leaves. A spontaneous mutant, TuMV-UK1 (UK1m), with the amino acid substitution V1827E in CI, broke Rnt1-1 resistance and altered the systemic necrosis and leaf malformation induced by rnt1-2. This single amino acid in the CI protein of UK1 was also associated with severe mosaic and abnormal leaf development, perhaps interacting with unknown host factors. To clarify the relationship between Rnt1-1 and TuRB01b, which was previously reported as a TuMV-UK1 resistance gene on chromosome R6, the B. rapa cultivar Tropical Delight carrying TuRB01b was inoculated with UK1m or the infectious UK1 clone with the CI V1827E mutation. Because Tropical Delight showed resistance to both mutants, Rnt1-1 might be different from TuRB01b.