RESUMO
Jao Hom Nin (JHN) is a Thai rice variety with broad-spectrum resistant against rice blast fungus. JHN contains two rice blast resistant genes, Pish and Pik, located on chromosome 1 and on chromosome 11, respectively. To understand the blast resistance in JHN, the study of the defense mechanism related to the Pish and Pik genes is crucial. This study aimed to dissect defense response genes between the Pish and Pik genes using the RNA-seq technique. Differentially expressed genes (DEGs) of Pish and Pik backcross inbred lines were identified between 0 and 24 h after inoculation with rice blast spore suspension. The results showed that 1248 and 858 DEGs were unique to the Pish and Pik lines, respectively. The wall-associated kinase gene was unique to the Pish line and the zinc-finger-containing protein gene was unique to the Pik line. Pathogenicity-related proteins PR-4 and PR-10 were commonly found in both Pish and Pik lines. Moreover, DEGs functionally categorized in brassinosteriod, jasmonic acid, and salicylic acid pathways were detected in both Pish and Pik lines. These unique and shared genes in the Pish and Pik rice blast defense responses will help to dissect the mechanisms of plant defense and facilitate rice blast breeding programs.
RESUMO
Rice is believed to have originated from Indo-China, area between China and India, and then spread throughout the world. The Indochina region mainly includes countries like Thailand, Laos and Vietnam, which are the world's major rice exporters. Rice varieties grown in this area are highly diverse due to their different environment, ecosystem and climatic conditions. The objective of this study was to evaluate the genetic relationship of Indochina rice varieties using intersimple sequence repeat (ISSR), sequence-related amplified polymorphism (SRAP) and insertion-deletion (InDel) markers. Forty-six rice varieties, including 16, 4,11 and 15 from Thailand, China, Laos and Vietnam, respectively were used in this study. Seventeen of the 20 ISSR primers showed 82.96% polymorphism. At the same time, 17 of the 30 primer pairs of SRAP marker showed clear DNA amplification, which resulted in 84.79% polymorphism. Ninety-seven of 133 InDel markers have about 99.47% polymorphism. Three markers showed average PIC score ranging from 0.20 to 0.26. When the analysis was conducted using UPGMA clustering method, it was found that the combined data from three markers gave a better result than each marker separately. The results from clustering analysis showed that all accessions can be grouped based on their location and can be categorized into two major groups. Useful results from this study could bring substantial benefits and ultimately help the rice breeders to develop elite rice varieties in future.
