Andres R J, Dunne J C
Department of Crop and Soil Sciences, North Carolina State University, Raleigh, NC, USA.
Theor Appl Genet. 2022 Oct;135(10):3433-3442. doi: 10.1007/s00122-022-04190-0. Epub 2022 Aug 11.
Contamination at the FAD2B locus due to inadequate screening protocols is the primary cause of sporadic, insufficient oleic acid content in Virginia-type peanut. The high oleic trait in peanut is conditioned by loss-of-function mutations in a pair of homeologous enzymes and is well known to improve the shelf life of peanut products. As such, the trait is given high priority in current and future cultivars by the North Carolina State University peanut breeding program. For unknown reasons, high oleic cultivars and breeding lines intermittently failed to meet self-imposed thresholds for oleic acid content in internal testing. To determine why, a manual seed chipper, crude DNA isolation protocol, genotyping assays for both mutations, and a web-based SNP calling application were developed. The primary cause was determined to be contamination with normal oleic seeds resulting from inadequate screening protocols. In order to correct the problem, a faster screening method was acquired to accommodate a higher oleic acid threshold. Additionally, results showed the mutation in one homeolog is fixed in the program, dig date had no significant effect on oleic acid content, and minor modifiers segregating within the program explained 6% of the variation in oleic acid content.
由于筛选方案不完善导致FAD2B基因座污染，是弗吉尼亚型花生中油酸含量偶尔不足的主要原因。花生的高油酸性状由一对同源酶的功能丧失突变决定，众所周知，这一性状可延长花生制品的保质期。因此，北卡罗来纳州立大学花生育种项目在当前和未来的品种中高度重视这一性状。由于不明原因，高油酸品种和育种系在内部测试中偶尔未能达到自行设定的油酸含量阈值。为了查明原因，开发了一种手动种子切片机、粗DNA提取方案、针对两种突变的基因分型检测方法以及一个基于网络的单核苷酸多态性（SNP）分型应用程序。经确定，主要原因是筛选方案不完善导致正常油酸种子的污染。为了解决这个问题，采用了一种更快的筛选方法，以适应更高的油酸阈值。此外，结果表明，该项目中一个同源基因的突变是固定的，收获日期对油酸含量没有显著影响，项目内分离的微小修饰基因解释了油酸含量6%的变异。
