Yogendra Kalenahalli N, Kushalappa Ajjamada C, Sarmiento Felipe, Rodriguez Ernesto, Mosquera Teresa
Plant Science Department, McGill University, Ste.-Anne-de-Bellevue, Quebec, H9X 3V9, Canada.
Departmento de Agronomia, Universidad National de Colombia, Bogota, Colombia.
Funct Plant Biol. 2015 Mar;42(3):284-298. doi: 10.1071/FP14177.
Resistance to late blight in potato is either qualitative or quantitative in nature. The quantitative resistance is durable, but the molecular and biochemical mechanisms underlying quantitative resistance are poorly understood, and are not efficiently utilised in potato breeding. A non-targeted metabolomics, using high resolution hybrid mass spectrometry, was applied to decipher the mechanisms of resistance in the advanced breeding diploid potato genotypes (Solanum tuberosum L. Group Phureja), with valuable sources of genetic diversity. The metabolomics profiles of resistant genotypes (AC04 and AC09) were compared with a susceptible commercial genotype (Criolla Colombia), following Phytophthora infestans or mock-inoculation, to identify the resistance related (RR) metabolites. Metabolites belonging to phenylpropanoids, flavonoid and alkaloid chemical groups were highly induced in resistant genotypes relative to susceptible. Concurrently, the biosynthetic genes, tyrosine decarboxylase (TyDC) and tyramine hydroxycinnamoyl transferase (THT), involved in the biosynthesis of hydroxycinnamic acid amides (HCAAs), and chalcone synthase (CHS) and flavonol synthase (FLS), involved in flavonoid biosynthesis, were also upregulated, as confirmed by quantitative real-time PCR. Probable genes coding for these enzymes were sequenced and nonsynonymous single-nucleotide polymorphisms (nsSNPs) were identified. The resistance to late blight observed in this study was mainly associated with cell wall thickening due to deposition of HCAAs, flavonoids and alkaloids.
马铃薯对晚疫病的抗性本质上要么是定性的，要么是定量的。定量抗性具有持久性，但对定量抗性背后的分子和生化机制了解甚少，并且在马铃薯育种中没有得到有效利用。利用高分辨率混合质谱的非靶向代谢组学方法，被用于解析具有宝贵遗传多样性来源的高级育种二倍体马铃薯基因型（Solanum tuberosum L. Group Phureja）的抗性机制。在致病疫霉接种或模拟接种后，将抗性基因型（AC04和AC09）的代谢组学图谱与易感商业基因型（Criolla Colombia）进行比较，以鉴定抗性相关（RR）代谢物。相对于易感基因型，属于苯丙烷类、黄酮类和生物碱化学组的代谢物在抗性基因型中被高度诱导。同时，参与羟基肉桂酸酰胺（HCAAs）生物合成的生物合成基因酪氨酸脱羧酶（TyDC）和酪胺羟基肉桂酰转移酶（THT），以及参与黄酮类生物合成的查尔酮合酶（CHS）和黄酮醇合酶（FLS），经定量实时PCR证实也被上调。对编码这些酶的可能基因进行了测序，并鉴定了非同义单核苷酸多态性（nsSNPs）。本研究中观察到的对晚疫病的抗性主要与由于HCAAs、黄酮类和生物碱的沉积导致的细胞壁增厚有关。
