Identification of QTLs responsible for culturability, and fine-mapping of QTL qCBT9 related to callus browning derived from Dongxiang common wild rice (Oryza rufipogon Griff.)

Xin Lou; Jingjing Su; Yuzhu Xiong; Min Chen; Qiaowen Zhang; Yanfang Luan; Chuanqing Sun; Yongcai Fu; Kun Zhang

doi:10.1007/s11032-024-01470-z

Identification of QTLs responsible for culturability, and fine-mapping of QTL qCBT9 related to callus browning derived from Dongxiang common wild rice (Oryza rufipogon Griff.)

Mol Breed. 2024 Apr 27;44(5):32. doi: 10.1007/s11032-024-01470-z. eCollection 2024 May.

Authors

Xin Lou^#¹, Jingjing Su^#¹, Yuzhu Xiong^#¹, Min Chen¹, Qiaowen Zhang², Yanfang Luan¹, Chuanqing Sun^{1

3}, Yongcai Fu¹, Kun Zhang¹

Affiliations

¹ National Center for Evaluation of Agricultural Wild Plants (Rice), Department of Plant Genetics and Breeding, China Agricultural University, Beijing, 100193 China.
² Agricultural Technology Extension Center of Dunhua City, Dunhua, 133700 China.
³ State Key Laboratory of Plant Physiology and Biochemistry, China Agricultural University, Beijing, 10093 China.

^# Contributed equally.

PMID: 38685957
PMCID: PMC11055834 (available on 2025-04-27)
DOI: 10.1007/s11032-024-01470-z

Abstract

Compared to japonica, the lower genetic transformation efficiency of indica is a technical bottleneck for rice molecular breeding. Specifically, callus browning frequently occurs during the culture of the elite indica 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, Oryza rufipogon Griff.) with 93-11 genetic background, explaining 4% ~12% of the phenotypic variations. The QTL qCBT9 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 F₂ population crossed of 93-11 and 9DIL71 and the recombinant plants screened from 3270 individuals. The qCBT9 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 qCBT9. Furthermore, callus browning may be involved in cell senescence and death caused by oxidative stress. The differentiation of indica and japonica in this region suggested that qCBT9 was possibly a vital QTL contributed to better culturability of japonica. Our results laid a foundation for further cloning of the gene for reduced callus browning in O. rufipogon, 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.

Keywords: Callus browning; Culturability; Dongxiang common wild rice; Fine mapping; QTL.

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