Identification of QTLs responsible for culturability, and fine-mapping of QTL related to callus browning derived from Dongxiang common wild rice ( Griff.).

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Compared to , the lower genetic transformation efficiency of is a technical bottleneck for rice molecular breeding. Specifically, callus browning frequently occurs during the culture of the elite variety 93-11, leading to poor culturability and lower genetic transformation efficiency. Here, 67 QTLs related to culturability were detected using 97 introgression lines (designated as 9DILs) derived from Dongxiang common wild rice (DXCWR, Griff.) with 93-11 genetic background, explaining 4% ~12% of the phenotypic variations. The QTL on chromosome 9 was a primary QTL for reducing callus browning derived from DXCWR. Five 9DILs with light callus browning and high differentiation were screened. We evaluated the callus browning index (CBI) of 100 F population crossed of 93-11 and 9DIL71 and the recombinant plants screened from 3270 individuals. The was delimited to a ~148kb region between the markers X16 and X23. RNA-seq analysis of DEGs between 9DIL71 and 93-11 showed three upregulated DEGs (Os09g0526500, Os09g0527900, Os09g0528200,) and three downregulated DEGs (Os09g0526700, Os09g0526800, Os09g0527700) were located in the candidate region of Furthermore, callus browning may be involved in cell senescence and death caused by oxidative stress. The differentiation of and in this region suggested that was possibly a vital QTL contributed to better culturability of . Our results laid a foundation for further cloning of the gene for reduced callus browning in . , and also provided a new genetic resource and material basis for improving the culturability and genetic transformation efficiency of cultivated rice.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s11032-024-01470-z.