Pataky Jerald K, Pate Molly C, Hulbert Scot H
Department of Crop Sciences, University of Illinois, Urbana 61801.
Department of Plant Pathology, Kansas State University, Manhattan 66506-5502.
Plant Dis. 2001 Feb;85(2):165-168. doi: 10.1094/PDIS.2001.85.2.165.
Resistance in sweet corn conferred by the Rp1-D gene has controlled common rust, caused by Puccinia sorghi, in North American corn for nearly 15 years. Eleven isolates of P. sorghi virulent on corn with the Rp1-D gene were collected from Rp-resistant corn in 1999 from Wiscon-sin, Illinois, New York, and Minnesota. Isolates were increased on susceptible sweet corn. Urediniospores of nine isolates were bulked. Reactions of individual Rp genes in the rp1 region and reactions of linked combinations of Rp genes in the rp1 region (i.e., compound rust resistance genes) were evaluated against the bulked population of P. sorghi in several greenhouse trials. Reactions of individual and compound Rp genes also were evaluated against individual isolates of P. sorghi. Each trial contained at least two replicates of several lines with Rp genes and one susceptible check. Five to 10 two-leaved seedlings per line were inoculated at least twice with a suspension of urediniospores. Ten days after inoculation, rust reactions were rated:+ = sporulating uredinia, - = no sporulating uredinia, and I = chlorotic or necrotic tissue surrounding small uredinia. Four single genes, Rp1-E, Rp-G, Rp1-I, and Rp1-K, and eight compound genes, Rp1-JFC, Rp1-JC, Rp-GI, Rp-G5, Rp-GDJ, Rp-G5JD, Rp-G5JC, and Rp-GFJ, conferred resistance. Additional characterization of virulence in North American populations of P. sorghi that are avirulent against Rp1-D is necessary to determine if these genes will be as widely effective as the Rp1-D gene has been. Two subpopulations of P. sorghi were detected from the bulked population after it was sequentially cultured for at least five cycles on seedlings with Rp1-C or with Rp1-J. The subpopulation cultured on Rp1-J was avirulent on lines with Rp1-C/L/N, Rp1-B, and Rp1-M; whereas the subpopulation cultured on Rp1-C was virulent on lines with each of these genes. Both subpopulations were virulent on lines with Rp1-D.
由Rp1-D基因赋予的甜玉米抗性已在近15年里控制了北美玉米上由高粱柄锈菌（Puccinia sorghi）引起的普通锈病。1999年从威斯康星州、伊利诺伊州、纽约州和明尼苏达州的Rp抗性玉米中收集到11株对带有Rp1-D基因的玉米具有毒性的高粱柄锈菌分离株。这些分离株在感病甜玉米上进行扩繁。将9个分离株的夏孢子堆放在一起。在几个温室试验中，针对高粱柄锈菌的混合群体评估了rp1区域中单个Rp基因的反应以及rp1区域中Rp基因连锁组合（即复合抗锈基因）的反应。还针对高粱柄锈菌的单个分离株评估了单个和复合Rp基因的反应。每个试验包含几个带有Rp基因的品系的至少两个重复以及一个感病对照。每个品系5至10株二叶期幼苗至少用夏孢子悬浮液接种两次。接种10天后，对锈病反应进行评级：+ = 产生夏孢子堆的夏孢子堆，- = 不产生夏孢子堆的夏孢子堆，I = 围绕小夏孢子堆的褪绿或坏死组织。四个单基因Rp-E、Rp-G、Rp-I和Rp-K以及八个复合基因Rp-JFC、Rp-JC、Rp-GI、Rp-G5、Rp-GDJ、Rp-G5JD、Rp-G5JC和Rp-GFJ表现出抗性。有必要对北美高粱柄锈菌群体中对Rp1-D无毒的毒力进行进一步表征，以确定这些基因是否会像Rp1-D基因一样广泛有效。在带有Rp1-C或Rp1-J的幼苗上连续培养至少五个周期后，从混合群体中检测到两个高粱柄锈菌亚群体。在Rp1-J上培养的亚群体对带有Rp1-C/L/N、Rp1-B和Rp1-M的品系无毒；而在Rp1-C上培养的亚群体对带有这些基因中每一个的品系有毒。两个亚群体对带有Rp1-D的品系均有毒。
