title: Molecular breeding of thermo-sensitive genic male sterile (TGMS) lines of rice for blast resistance using Pi2 gene.
abstract: BACKGROUND
  Blast disease caused by the fungal pathogen Magnaporthe oryzae is one of the big problems in rice production in China, especially for high yield hybrid varieties made from a two-line system in which thermo-sensitive genic male sterile (TGMS) lines are used. In this study, we report the introgression of a rice blast resistance gene Pi2 from VE6219 into C815S, an elite rice TGMS line, leading to the development of blast resistant TGMS lines through marker assisted selection (MAS) and phenotypic selection approaches.
  
  
  RESULTS
  Four new TGMS lines with blast resistance gene Pi2 were developed from C815S (an elite TGMS line susceptible to the blast, used as recurrent parent) and VE6219 (a blast resistant line harboring Pi2, used as donor parent). The pathogenicity assays inoculated with 53 blast prevalent isolates in glasshouse showed that the blast resistant frequency of the four TGMS lines was 94.3%-98.1% that is equivalent to blast resistant donor parent VE6219. The field evaluation of the new lines and hybrids made from them at a blast epidemic site also showed high resistant levels against the blast. The genetic background of the newly developed TGMS lines were examined using a whole-genome single nucleotide polymorphism (SNP) array (RICE6K) that turned out more than 83% of the genomic markers were derived from the recurrent parent. The critical temperature points of fertility-sterility alteration of the new TGMS lines were between 22°C and 23°C of daily mean temperature, which is similar to that of C815S. The complete male sterility under natural growth conditions at Wuhan last more than 80 days. Their agronomic and grain quality traits meet the requirement for two-line hybrid rice production.
  
  
  CONCLUSIONS
  The broad-spectrum and durable rice blast resistant gene Pi2 was introgressed into the elite TGMS line C815S background. The newly developed TGMS lines can be practically used for two-line hybrid rice breeding and must play an important role in sustainable rice production in China.
authors.affiliation: National Key Laboratory of Crop Genetic Improvement, National Center of Plant Gene Research (Wuhan), Huazhong Agricultural University, Wuhan, 430070 China.
authors.forename: Jiefeng
authors.initials: J
authors.lastname: Jiang
authors.affiliation: National Key Laboratory of Crop Genetic Improvement, National Center of Plant Gene Research (Wuhan), Huazhong Agricultural University, Wuhan, 430070 China.
authors.forename: Tongmin
authors.initials: T
authors.lastname: Mou
authors.affiliation: Life Science and Technology Center, China National Seed Group Co., Ltd., Wuhan, 430206 China.
authors.forename: Huihui
authors.initials: H
authors.lastname: Yu
authors.affiliation: Life Science and Technology Center, China National Seed Group Co., Ltd., Wuhan, 430206 China.
authors.forename: Fasong
authors.initials: F
authors.lastname: Zhou
keywords: Marker-assisted selection; Pi2; Rice blast resistance; TGMS line; Two-line hybrid rice
references.citation: Theor Appl Genet. 2012 May;124(7):1295-304
references.pmid: 22270148
references.citation: Plant Cell. 2000 Dec;12(12):2473-2484
references.pmid: 11148291
references.citation: Proc Natl Acad Sci U S A. 1994 Aug 30;91(18):8675-9
references.pmid: 7915844
references.citation: Plant Biotechnol J. 2014 Jan;12(1):28-37
references.pmid: 24034357
references.citation: Theor Appl Genet. 2013 Apr;126(4):985-98
references.pmid: 23400829
references.citation: Proc Natl Acad Sci U S A. 2012 Feb 14;109(7):2654-9
references.pmid: 22308482
references.citation: Theor Appl Genet. 2008 Oct;117(6):935-45
references.pmid: 18726584
references.citation: Theor Appl Genet. 2004 May;108(7):1212-20
references.pmid: 14740086
references.citation: Theor Appl Genet. 2011 Feb;122(2):365-72
references.pmid: 20938764
references.citation: Theor Appl Genet. 2006 Aug;113(4):705-13
references.pmid: 16832648
references.citation: Mol Plant Pathol. 2010 May;11(3):419-27
references.pmid: 20447289
references.citation: Mol Genet Genomics. 2001 Oct;266(2):271-5
references.pmid: 11683269
references.citation: Mol Genet Genomics. 2002 Jun;267(4):472-80
references.pmid: 12111554
references.citation: Mol Plant. 2014 Mar;7(3):541-53
references.pmid: 24121292
references.citation: Trends Biotechnol. 2009 Mar;27(3):141-50
references.pmid: 19187990
references.citation: Mol Genet Genomics. 2005 Jul;273(6):507-11
references.pmid: 15912317
references.citation: Rice (N Y). 2013 Feb 08;6(1):5
references.pmid: 24280417
references.citation: Rice (N Y). 2014 Apr 10;7(1):2
references.pmid: 24920970
references.citation: Mol Plant Microbe Interact. 2006 Nov;19(11):1216-28
references.pmid: 17073304
references.citation: Plant Physiol. 2001 Dec;127(4):1425-9
references.pmid: 11743085