Expression Profile of Defense Genes in Rice Lines Pyramided with Resistance Genes Against Bacterial Blight, Fungal Blast and Insect Gall Midge

Abstract

BackgroundRice, a major food crop of the world, endures many major biotic stresses like bacterial blight (BB), fungal blast (BL) and the insect Asian rice gall midge (GM) that cause significant yield losses. Progress in tagging, mapping and cloning of several resistance (R) genes against aforesaid stresses has led to marker assisted multigene introgression into elite cultivars for multiple and durable resistance. However, no detailed study has been made on possible interactions among these genes when expressed simultaneously under combined stresses.ResultsOur studies monitored expression profiles of 14 defense related genes in 11 rice breeding lines derived from an elite cultivar with different combination of R genes against BB, BL and GM under single and multiple challenge. Four of the genes found implicated earlier under combined GM and BB stress were confirmed to be induced (≥ 2 fold) in stem tissue following GM infestation; while one of these, cytochrome P450 family protein, was also induced in leaf in plants challenged by either BB or BL but not together. Three of the genes highlighted earlier in plants challenged by both BB and BL were also found induced in stem under GM challenge. Pi54 the target R gene against BL was also found induced when challenged by GM. Though expression of some genes was noted to be inhibited under combined pest challenge, such effects did not result in compromise in resistance against any of the target pests.ConclusionWhile R genes generally tended to respond to specific pest challenge, several of the downstream defense genes responded to multiple pest challenge either single, sequential or simultaneous, without any distinct antagonism in expression of resistance to the target pests in two of the pyramided lines RPNF05 and RPNF08.Electronic supplementary materialThe online version of this article (10.1186/s12284-018-0231-4) contains supplementary material, which is available to authorized users.

Development of ‘multiresistance rice’ by an assembly of herbicide, insect and disease resistance genes with a transgene stacking system

“…Therefore, there was no need to introduce hygromycin and other screening marker genes to avoid the problems caused by the existence of marker genes. Generally, the aggregation and co‐expression of multiple resistance genes in the same plant would result in resistance to all target pests and diseases 3 . However, co‐expression of some resistance genes may also have antagonistic effects that lead to the loss of resistance.…”

“…Generally, the aggregation and co-expression of multiple resistance genes in the same plant would result in resistance to all target pests and diseases. 3 However, co-expression of some resistance genes may also have antagonistic effects that lead to the loss of resistance. Therefore, to obtain rice varieties with superior multiresistance, it is critical to rationally select resistance genes from abundant resistance gene resources to be combined, which is the premise to ensure the normal function of each gene.…”

“…Generally, the most effective way to manage diseases and pests is the application of pesticides or cultivation of resistant varieties, but the application of excessive pesticides will certainly cause pollution to rice products and the environment 2 . Practice has demonstrated that cultivation of herbicide‐ and pest‐resistant rice varieties is the most economical, safe and effective measure to control weeds, diseases and pests 3,4 . Currently, a large number of genes derived from rice and microorganisms with resistance against herbicides, borers, brown planthopper, bacterial blight and rice blast have been cloned, making it more possible to breed and cultivate multiresistant rice varieties to control weeds, pests and diseases in a more economical, effective and environmentally friendly way.…”

“…2 Practice has demonstrated that cultivation of herbicide-and pest-resistant rice varieties is the most economical, safe and effective measure to control weeds, diseases and pests. 3,4 Currently, a large number of genes derived from rice and microorganisms with resistance against herbicides, borers, brown planthopper, bacterial blight and rice blast have been cloned, making it more possible to breed and cultivate multiresistant rice varieties to control weeds, pests and diseases in a more economical, effective and environmentally friendly way. Although molecular breeding can assemble multiple resistance genes from rice sources through sexual hybridization, it is time-consuming and laborious; besides, it may introduce adverse genes together with resistance genes, which may negatively affect the desirable traits of the original varieties.…”

Study on Transcriptional Responses and Identification of Ribosomal Protein Genes for Potential Resistance against Brown Planthopper and Gall Midge Pests in Rice

“…BPT5204 is susceptible to both pests and is obtained from the Indian Institute of Rice Research, Hyderabad, India. RPNF05, which has been shown to exhibit moderate to a high level of resistance against BPH and GM, respectively is collected from the Agri Biotech Foundation, Hyderabad, India [ 41 , 42 ] and is used as a positive control. It is a derivative of BPT5204 obtained by systematic introgression of bacterial blight ( Xa21, xa13 and xa5 ), fungal blast ( Pi54 ) and GM resistance genes ( Gm1, Gm3, Gm4 and Gm8 ) [ 42 ].…”