Simko Ivan, Hasegawa Daniel K, Peng Hui, Zhao Rebecca
Crop Improvement and Protection Research Unit, Agricultural Research Service, U.S. Department of Agriculture, Salinas, CA, United States.
Horticultural Sciences Department, Everglades Research and Education Center, University of Florida, Belle Glade, FL, United States.
Front Plant Sci. 2023 Jun 8;14:1163683. doi: 10.3389/fpls.2023.1163683. eCollection 2023.
Impatiens necrotic spot virus (INSV) is a major pathogen currently threatening lettuce ( L.) production in the coastal areas of California. The virus is transmitted by the western flower thrips (Frankliniella occidentalis Pergande).
We have tested a diversity panel of almost 500 lettuce accessions for disease incidence (DI) in 12 field experiments performed over 7 years. This set of accessions was also assessed for thrips feeding damage (TFD), the rate of plant development (PD), and the content of chlorophyll (SPAD) and anthocyanins (ACI) to determine their effect on resistance to INSV. In addition, recombinant inbred lines from two biparental mapping populations were also evaluated for DI in field experiments.
The mean DI in 14 field experiments ranged from 2.1% to 70.4%. A highly significant difference in DI was observed among the tested accessions, with the overall lowest DI detected in the red color cultivars, Outredgeous Selection, Red Splash Cos, Infantry, Sweet Valentine, Annapolis, and Velvet. Multiple linear regression models revealed a small but significant effect ( < 0.005) of the four analyzed determinants on DI. Accessions with lower DI values had slower plant development (PD, = 0.352), higher ACI content ( = -0.284), lower TFD ( = 0.198), and lower SPAD content ( = 0.125). A genome-wide association study revealed 13 QTLs for DI located on eight out of the nine lettuce chromosomes (the exception was chr. 8). The most frequently detected QTL () was located on chr. 2. Several of the QTLs for DI were in the same genomic areas as QTLs for PD, ACI, and SPAD. Additional three QTLs for DI on chr. 5 and 8 were identified using linkage mapping performed on two biparental mapping populations.
The work highlights the genetic basis of partial resistance to INSV and reveals the relationship between resistance, the host physiology, and the thrips vector. Results of this study are an important steppingstone toward developing cultivars with increased resistance against INSV.
凤仙坏死斑点病毒（INSV）是目前威胁加利福尼亚沿海地区生菜（L.）生产的一种主要病原体。该病毒由西花蓟马（Frankliniella occidentalis Pergande）传播。
我们在7年期间进行的12次田间试验中，对近500份生菜种质资源的多样性样本进行了发病率（DI）测试。还对这组种质资源的蓟马取食损伤（TFD）、植株发育速率（PD）、叶绿素含量（SPAD）和花青素含量（ACI）进行了评估，以确定它们对INSV抗性的影响。此外，还在田间试验中对来自两个双亲作图群体的重组自交系进行了DI评估。
14次田间试验中的平均DI在2.1%至70.4%之间。在测试的种质资源中观察到DI存在极显著差异，在红色品种Outredgeous Selection、Red Splash Cos、Infantry、Sweet Valentine、Annapolis和Velvet中检测到的总体DI最低。多元线性回归模型显示，四个分析决定因素对DI有微小但显著的影响（<0.005）。DI值较低的种质资源植株发育较慢（PD，=0.352），ACI含量较高（=-0.284），TFD较低（=0.198），SPAD含量较低（=0.125）。全基因组关联研究揭示了9条生菜染色体中8条上的13个DI的QTL（第8号染色体除外）。最常检测到的QTL（）位于第2号染色体上。几个DI的QTL与PD、ACI和SPAD的QTL位于相同的基因组区域。利用对两个双亲作图群体进行的连锁作图，在第5号和第8号染色体上鉴定出另外3个DI的QTL。
这项工作突出了对INSV部分抗性的遗传基础，并揭示了抗性、寄主生理学和蓟马传播媒介之间的关系。本研究结果是培育对INSV抗性增强品种的重要基石。
