西葫芦PRSV-W病毒病抗病种质鉴定及抗性遗传分析

番木瓜环斑病毒西瓜株系(PRSV-W)是危害西葫芦生产的主要病害之一,为减少产量损失,加快西葫芦抗病品种的选育,本研究拟通过人工苗期子叶摩擦接种,结合酶联免疫吸附测定法(ELISA)及反转录PCR(RT-PCR)检测分析,建立西葫芦PRSV-W抗性鉴定技术,并对148份西葫芦品种及高代自交系育种材料进行抗性评价,同时利用抗、感自交系构建六世代群体,探究西葫芦PRSV-W抗性遗传规律。结果表明,播种2周后最适宜对子叶进行病毒摩擦接种。接种病毒15~25 d后西葫芦抗、感特性表现充分,易于鉴别,从高抗到高感可分为0~4级。148份西葫芦种质材料中,22份种质材料表现为高度抗病,11份种质材料表现为抗病,总抗病种质材料占比22.3%;12份种质材料表现为感病,103份种质材料表现为高度感病,总感病种质材料占比77.7%。此外,在叶片组织的病毒检测中,RT-PCR技术比ELISA更为灵敏准确;在西葫芦高抗自交系BV21中,PRSV-W抗性受1对显性抗病基因控制。本研究结果为西葫芦PRSV-W抗病育种提供了种质材料及技术支持。

Characterization and Inheritance of Resistance to PRSV-W (Papaya Ringspot Virus-Watermelon Strain) in Squash (Cucurbita pepo L.)

The watermelon strain of papaya ringspot virus-watermelon strain (PRSV-W) is one of potyviruses causing severe damage to the production of cucurbit crops including squash. To develop an evaluation technique, and find genetic resources for PRSV-W resistance in squash, one hundred and forty eight accessions were manually inoculated with PRSV-W. Levels of resistance to PRSV-W accumulation in squash leaf tissue were evaluated using a combination of visual symptom observation, ELISA and RT-PCR analysis. Inheritance of resistance to PRSV-W in inbred line BV21 was also analyzed with six generations (parents, generations F₁, F₂ and F₁BC₁ for both parents). The results showed that the best approach for evaluating resistance to PRSV-W in squash plants was to inoculate the cotyledons of 2-week-old seedlings with virus, and then to rate the symptom expression of first to third leaves after 15 to 25 days. Plants were classified for PRSV symptom severity on a scale from 0 (no symptoms) to 4 (severe symptoms). Among the 148 accessions screened, 22 showed high tolerant, 11 exhibited moderately tolerant, total disease-resistant germplasm materials accounted of 22.3%; 12 exhibited susceptibility, 103 germplasm materials were highly susceptible the total susceptible germplasm materials accounted for 77.7%. RT-PCR was more precise and sensitive than ELISA in virus detection. The genetic analysis results revealed that a single dominant gene conferred resistance to PRSV-W in BV21 and its generation. These results will facilitate development of resistant varieties to control this disease.