Hamamouch Noureddine, Winkel Brenda S J, Li Chunying, Davis Eric L
North Carolina State University, Department of Entomology & Plant Pathology, Raleigh, NC 27695, USA.
Laboratory of Biotechnology and Sustainable Development of Natural Resources, Polydisciplinary Faculty, University Sultan Moulay Slimane, Beni Mellal 23000, Morocco.
Plants (Basel). 2020 Feb 17;9(2):253. doi: 10.3390/plants9020253.
Although it is well established that flavonoid synthesis is induced in diverse plant species during nematode parasitism, little is known about the regulation of genes controlling flavonol biosynthesis during the plant-nematode interaction. In this study, expression of the flavonol-specific transcription factor, , the flavonol synthase genes, , , , , and , and the gene encoding the central flavonoid enzyme, chalcone synthase (), were examined in plant roots during infection by (sugar beet cyst) and (root-knot) nematodes. These experiments showed that was transiently upregulated at 9 dpi in syncytia associated with sugar beet cyst nematode infection and that an -deficient line was less susceptible to the parasite. This suggests that, rather than contributing to plant defense, this gene is essential for productive infection. However, the and genes, which are controlled by AtMYB12, did not exhibit a similar transient increase, but rather were expressly downregulated in syncytia relative to adjacent uninfected root tissue. Genetic analyses further indicated that contributes to plant defense against Cyst nematode infection, while other gene family members do not, consistent with prior reports that these other genes encode little or no enzyme activity. Together, these findings indicate a role of in promoting the early stages of Cyst nematode infection, while flavonols produced through the action of AtFLS1 are essential for plant defense. On the other hand, a transient induction of was not observed in galls produced during root-knot nematode infection, but this gene was instead substantially downregulated, starting at the 9 dpi sampling point, as were and In addition, both the - and -deficient lines were more susceptible to infection by this parasite. There was again little evidence for contributions from the other gene family members, although an -deficient line appeared to be somewhat more susceptible to infection. Taken together, this study shows that sugar-beet cyst and root-knot nematodes modulate differently the genes involved in flavonol biosynthesis in order to successfully infect host roots and that AtFLS1 may be involved in the plant basal defense response against nematode infection.
尽管黄酮类化合物的合成在多种植物物种受到线虫寄生时被诱导这一点已得到充分证实，但对于植物与线虫相互作用过程中控制黄酮醇生物合成的基因调控却知之甚少。在本研究中，检测了黄酮醇特异性转录因子、黄酮醇合酶基因、、、、和，以及编码核心黄酮类酶查尔酮合酶（）的基因在植物根部受（甜菜胞囊线虫）和（根结线虫）感染期间的表达情况。这些实验表明，在与甜菜胞囊线虫感染相关的合胞体中，在感染后第9天短暂上调，并且一个缺失的品系对该寄生虫的易感性较低。这表明，该基因并非有助于植物防御，而是对有效感染至关重要。然而，受AtMYB12调控的和基因并未表现出类似的短暂增加，而是相对于相邻未感染的根组织，在合胞体中明显下调。遗传分析进一步表明，有助于植物抵御胞囊线虫感染，而其他基因家族成员则不然，这与之前的报道一致，即这些其他基因编码的酶活性很少或没有。总之，这些发现表明在促进胞囊线虫感染的早期阶段起作用，而通过AtFLS1的作用产生的黄酮醇对植物防御至关重要。另一方面，在根结线虫感染期间产生的虫瘿中未观察到的短暂诱导，但该基因反而从感染后第9天的采样点开始大幅下调，和也是如此。此外，缺失和的品系对这种寄生虫的感染更易感。同样，几乎没有证据表明其他基因家族成员有贡献，尽管一个缺失的品系似乎对感染更易感。综上所述，本研究表明甜菜胞囊线虫和根结线虫以不同方式调节参与黄酮醇生物合成的基因，以便成功感染宿主根，并且AtFLS1可能参与植物对线虫感染的基础防御反应。
