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Blast, caused by the ascomycete fungus Magnaporthe oryzae, is one of the most devastating diseases of rice due to the high variation of the pathogen. Breeding high-yielding rice cultivar with durable resistance to rice blast is a priority in Southern China and in places where rice cultivation is an important branch in farming. Effectiveness and accuracy of resistant cultivar breeding largely depend on the development of markers specific to the target gene. In silico prediction of the resistance (R) Pi39 gene content of the interval was made and hence a candidate gene was identified to develop a perfect insertion–deletion (InDel) based marker for Pi39 gene selection. The Pi39 gene was successfully introgressed in two elite cultivars using both foreground (the InDel) and background (genome-wide microsatellites) genotypic and phenotypic selection. Five selected BC3F3 progeny lines were recovered and showed a high level of blast resistance. At least 97.5% of their genome was inherited from their recurrent par...

Rice blast resistance (R) genes-mediated resistance response depends on various resistance-related genes involved in incompatible interactions. In this work, the expression profiles of innate rice immunity related genes were examined in the mediated resistance response of true/field resistance genes. Three sets of rice near-isogenic lines (NILs) were used: the resistant NILs carrying true resistance genes in the genetic background of the susceptible cultivar Nipponbare (NB), NB-Pib, NB-Pizt, NB-Pik and NB-Pita2; NILs bearing field resistance genes pi21 in the susceptible cultivar Aichiasahi (AA) AA-pi21, Kahei (KHR). The marker gene OsWRKY45 of salicylic acid (SA) signalling was upregulated in all tested cultivars. And, JAmyb (marker gene of jasmonic acid signalling) showed higher upregulation in the resistance lines with nucleotide-binding sites and leucine-rich repeat (NBS-LRR) R genes Pib, Pizt, Pik, Pita2 and Pikahei than in NB and KHS. SalT of abscisic acid (ABA) signalling may be involved in the R/Avr interaction, including Pizt, Pik, pi21 and Pikahei. However, SalT was shown to negatively regulate Pib/AvrPib interaction. OsPR1b and PBZ1 were differentially expressed and strongly activated at a later stage by 48 h post-inoculation. Interestingly, there was evidence that OsPR1b and PBZ1 played an important role in the pi21-mediated response. It was shown that OsRAR1 could be upregulated in the true resistance line NB-Pita2 and the field resistance line KHR, while OsSGT1 and OsHSP90 could be upregulated in all tested lines. The involvement of these genes illustrated the complexity of the downstream signalling pathways in the mediated resistance response of true/field resistance genes.