Cytogenetic mapping of the ALMT (aluminum-activated malate transporter) gene in wheat genotypes

ABSTRACT: Presence of the ALMT1 (aluminum-activated malate transporter) gene confers resistance to aluminum toxicity in Triticum aestivum (common wheat). No resistant cultivars of Triticum turgidum ssp. Durum Desf. (durum wheat) have been registered in Brazil. The aim of this study was to map the ALMT1 through application of the FISH (fluorescence in situ hybridization) technique in five wheat genotypes, common and durum, from the Active Germplasm Bank (AGB) of the Instituto Agronômico (IAC): BH 1146, P19, P33, Anahuac, and IAC 1003. FISH-ALMT1 signals were registered in Anahuac (sensitive) chromosomes and in BH 1146, P19, and P33 (resistant) chromosomes. In the three resistant genotypes, a characteristic double FISH signal was found, located in different chromosomes of the complements: in BH 1146 in chromosome 5D, in P19 in 3B, and in P33 in 6B. This FISH - ALMT1 mapping allows for introgression of aluminum resistance in sensitive cultivars through breeding programs using introgression lines containing these carrier chromosomes.

摘要：铝激活苹果酸转运蛋白（ALMT1）基因的存在可赋予普通小麦（Triticum aestivum）铝毒性抗性。目前巴西尚未注册过硬粒小麦（Triticum turgidum ssp. Durum Desf.）的抗性品系。本研究旨在借助荧光原位杂交（fluorescence in situ hybridization，FISH）技术，对来自农业研究所（Instituto Agronômico，IAC）活性种质库（Active Germplasm Bank，AGB）的5份小麦基因型（涵盖普通小麦与硬粒小麦）开展ALMT1基因定位，供试材料包括BH 1146、P19、P33、Anahuac以及IAC 1003。研究在敏感品种Anahuac的染色体，以及BH 1146、P19、P33这3个抗性品种的染色体上均检测到了FISH-ALMT1信号。在这3个抗性基因型中，均观察到特征性的双FISH信号，且定位在不同的染色体组染色体上：BH 1146的信号位于5D染色体，P19位于3B染色体，P33位于6B染色体。本研究建立的FISH-ALMT1定位方法，可通过携带上述目标染色体的渐渗系，借助育种程序实现敏感品种的铝抗性基因渐渗。