比利时的新型甜菜坏死黄脉病毒P25变体

Decroës A, Clausse M, Galein V, Legreve A, Wauters A, Bragard C

Commun Agric Appl Biol Sci. 2015;80(3):407-9.

Rhizomania is a widespread viral plant disease of major importance in sugar beet cropping and breeding. It is caused by the Beet necrotic yellow vein virus (BNYVV), a Benyvirus transmitted by the soil inhabiting plasmodiophorid Polymyxa betae. This vector also transmits other sugar beet virus such as Beet virus Q (BVQ) and Beet soil-borne virus (BSBV). Despite identification of resistance genes, BNYVV remains a major constraint because of resistance-breaking events as well as its ability to survive for long periods in soils in resting spores of P. betae. During the 2014 growing season, severe rhizomania symptoms were detected in Rz1 resistant beet genotypes in ten Belgian fields suggesting resistance-breaking events. Plants from these fields were sampled and total RNA was extracted from root hairs. The presence of BNYVV, BSBV, BVQ and P. betae was assessed by multiplex RT-PCR. Samples were then tested for the presence of BNYVV RNA5 and RNA3 by RT-PCR respectively targeting P26 and P25 genes. PCR products from P25 gene were then purified and sequenced. The results confirmed the presence of P. betae, BSBV and BVQ in all samples. BNYVV was detected in nine fields. Sequencing of P25 partial cDNA sequences revealed the presence of BNYVV types A and B. Two isolates possessed the amino acids motifs AYPR in the so-called tetrad region aa67-70. This motif was previously associated with resistance-breaking events. The Belgian situation will be discussed in the light of the current situation in neighbouring countries.

根肿病是一种在甜菜种植和育种中具有重要意义的广泛传播的病毒性植物病害。它由甜菜坏死黄脉病毒（BNYVV）引起，BNYVV是一种由土壤中的根肿菌多黏菌传播的甜菜病毒属病毒。这种传播介体还传播其他甜菜病毒，如甜菜病毒Q（BVQ）和甜菜土壤传播病毒（BSBV）。尽管已鉴定出抗性基因，但由于抗性突破事件以及其能够在多黏菌的休眠孢子中长期存活于土壤中，BNYVV仍然是一个主要限制因素。在2014年生长季节，在比利时的十个田地中，在Rz1抗性甜菜基因型中检测到严重的根肿病症状，表明发生了抗性突破事件。对这些田地的植株进行采样，并从根毛中提取总RNA。通过多重逆转录聚合酶链反应（RT-PCR）评估BNYVV、BSBV、BVQ和多黏菌的存在情况。然后分别通过针对P26和P25基因的RT-PCR检测样品中BNYVV RNA5和RNA3的存在情况。然后对来自P25基因的PCR产物进行纯化和测序。结果证实所有样品中均存在多黏菌、BSBV和BVQ。在九个田地中检测到BNYVV。P25部分cDNA序列的测序揭示了BNYVV A型和B型的存在。两个分离株在所谓的四分体区域aa67 - 70中具有氨基酸基序AYPR。该基序先前与抗性突破事件有关。将根据邻国的现状讨论比利时的情况。