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Background: Cold damage of maize during germination is a global problem; it occurs frequently in northeast China, and leads to a large-scale reduction in yield. Low temperature tolerance of maize in germination is a complex quantitative trait controlled by multigenes, and no major QTLs or key genes have been identified. Results: An F2 isolation population with S319 and R144 as parents was constructed. The bulked segregant analysis (BSA) and specific-locus amplified fragment-sequencing (SLAF-seq) methods were applied to locate the chromosomal association regions related to low-temperature tolerance of maize during germination. Sequencing obtained 221.72 Gbp clean data, with an average sequencing depth of 25.96X. Four candidate regions associated with low-temperature tolerance trait of maize in germination were obtained, with a total length of 25.71 Mb and 1513 annotated genes, including 456 nonsynonymous mutant genes and 111 frameshift mutant genes. Conclusions: This study aimed to lay the foundation for the mining of candidate genes of low-temperature tolerance in maize during germination, and accelerate the process of targeted improvement of maize low-temperature tolerance molecular marker-assisted breeding.How to cite: Yu T, Zhang J, Cao J, et al. QTL analysis of low temperature tolerance in maize germination by SLAF-seq and BSA technique. Electron J Biotechnol 2024;70. https://doi.org/10.1016/j.ejbt.2024.04.003.

Background: Cold injury is one of the most important limiting factors for maize production in mid-high latitude regions in the world. A total of 314 QTLs for maize low temperature tolerance have been identified in different populations using different statistical methods. However, few identical QTLs have been identified in different research studies. Results: A consensus map of QTLs related to maize low temperature tolerance was constructed, based on the public genetic map, IBM2 2008 Neighbors as a reference map, along with a set of 314 QTLs reported in the literature over the past 20 years. A total of 187 QTLs were projected onto the IBM2 2008 Neighbors by software BioMercator. Forty-seven consensus QTLs were detected. The confidence interval at all sites ranged from 0.04 cM to 102.73 cM, and the proportion of the phenotypic variance associated with each of them ranged from 3.32% to 20.11%. Major chromosomal sites were identified on Chr.6 (MQTL29, MQTL30, and MQTL31). Conclusions: This study provides further insights into the genetic basis of maize low temperature tolerance. Moreover, the MQTLs reported here could be harnessed for functional marker development and candidate gene mining of maize low temperature tolerance.How to cite: Yu T, Zhang J, Cao J, et al. A meta-analysis of low temperature tolerance QTL in maize. Electron J Biotechnol 2022;58. https://doi.org/10.1016/j.ejbt.2022.05.002

Weighted gene co-expression network analysis (WGCNA) is a research method in systematic biology. It is widely used to identify gene modules related to target traits in multi-sample transcriptome data. In order to further explore the molecular mechanism of maize response to low-temperature stress at the seedling stage, B144 (cold stress tolerant) and Q319 (cold stress sensitive) provided by the Maize Research Institute of Heilongjiang Academy of Agricultural Sciences were used as experimental materials, and both inbred lines were treated with 5 °C for 0 h, 12 h, and 24 h, with the untreated material as a control. Eighteen leaf samples were used for transcriptome sequencing, with three biological replicates. Based on the above transcriptome data, co-expression networks of weighted genes associated with low-temperature-tolerance traits were constructed by WGCNA. Twelve gene modules significantly related to low-temperature tolerance at the seedling stage were obtained, and a number of hub genes involved in low-temperature stress regulation pathways were discovered from the four modules with the highest correlation with target traits. These results provide clues for further study on the molecular genetic mechanisms of low-temperature tolerance in maize at the seedling stage.