全球气候变化正在对地球的环境产生日益重要的影响,而作物生产取决于作物基因型和环境之间的相互作用。利用现代生物学技术可以在分子水平上精细解析作物的基因型及其各个遗传组分对于表现型的贡献。然而对于作物具有重大影响的环境因子,目前,只能通过作物在不同环境下的表现型来推测其综合作用,或对整个试验区的个别环境因子进行对比分析,因而无法对各类环境因子进行深入剖析。笔者首次在国际上提出了环境型鉴定概念,并创造了一个英文新词etyping来表示。在本文中,环境型鉴定用envirotyping来代替。环境型(envirotype)用来描述包括所有影响作物不同生长发育阶段的内部和外部环境因子及其各种组合,外部环境因子主要包括水、肥、气、热、光、土壤、耕作制度和伴生生物等;而环境型鉴定用来表述对所有环境因子的解析和测定。环境型信息可以通过多种方式采集。作物多年多点区域试验积累了大量相关试验点的环境数据;地理信息系统(geographic information system,GIS)和土壤信息系统积累了大量气候、天气、土壤的数据;小型气象站可以监测小范围的天气、降雨、温度、气流等气象因子。众多环境检测仪器的使用,可以大规模采集与植物冠层、植物周边甚至单个试验小区和单个测试材料有关的土壤、光照、温度、水分、病虫害、伴生生物等外界环境因子。环境型信息将日益广泛应用于环境及其特征性鉴定、作物基因型-环境型互作、表现型预测、病虫害流行预测、近等环境型(near iso-envirotype)确定、作物对特定环境的反应研究、农艺组学(agronomic genomics)、精准高效农业等。展望未来,环境型鉴定需要将研究对象聚焦在单个材料的水平,实现单个材料的相关环境因子不同阶段的动态鉴定;需要开发和建立与基因型、表现型相结合的综合信息�
Gray leaf spot(GLS),caused by Cercospora zeae-maydis,is an important foliar disease of maize(Zea mays L.)worldwide,resistance to which is controlled by multiple quantitative trait loci(QTL).To gain insights into the genetic architecture underlying the resistance to this disease,an association mapping population consisting of 161 inbred lines was evaluated for resistance to GLS in a plant pathology nursery at Shenyang in 2010 and 2011.Subsequently,a genome-wide association study,using 41,101 single-nucleotide polymorphisms(SNPs),identified 51 SNPs significantly(P<0.001)associated with GLS resistance,which could be converted into 31 QTL.In addition,three candidate genes related to plant defense were identified,including nucleotidebinding-site/leucine-rich repeat,receptor-like kinase genes similar to those involved in basal defense.Two genic SNPs,PZE-103142893 and PZE-109119001,associated with GLS resistance in chromosome bins 3.07 and 9.07,can be used for marker-assisted selection(MAS)of GLS resistance.These results provide an important resource for developing molecular markers closely linked with the target trait,enhancing breeding efficiency.
Head smut, caused by the fungal pathogen Sporisorium reilianum, poses a grave threat to maize(Zea mays) production worldwide. Here we report cytological and molecular evidence for maize resistance to head smut. During early stages of root infection, S. reilianum mycelium was capable of penetrating the root epidermis of both resistant(Ji1037) and susceptible(HZ4) inbred lines. S. reilianum hyphae were observed in the root–stem junction at 6 days after inoculation. In an attempt to monitor hyphal spread within the maize plant,a highly specific and sensitive real-time PCR method was established to estimate the hyphal content in infected maize tissues. During the upward growth of endophytic S.reilianum, the extent of hyphal spread was markedly different between Ji1037 and HZ4. Very little or no pathogen was detected in aerial parts of Ji1037, whereas large amounts of pathogen accumulated in aboveground tissues, particularly inflorescences, of HZ4. Thus,maize resistance to S. reilianum was achieved mainly by inhibition of endophytic hyphal growth rather than by prevention of early-root penetration by the pathogen.
