QTL Mapping and Candidate Gene Analysis of Telomere Length Control Factors in Maize (Zea maysL.)

Abstract

Telomere length is a quantitative trait important for many cellular functions. Failure to regulate telomere length contributes to genomic instability, cellular senescence, cancer, and apoptosis in humans, but the functional significance of telomere regulation in plants is much less well understood. To gain a better understanding of telomere biology in plants, we used quantitative trait locus (QTL) mapping to identify genetic elements that control telomere length variation in maize (Zea mays L.). For this purpose, we measured the median and mean telomere lengths from 178 recombinant inbred lines of the IBM mapping population and found multiple regions that collectively accounted for 33–38% of the variation in telomere length. Two-way analysis of variance revealed interaction between the quantitative trait loci at genetic bin positions 2.09 and 5.04. Candidate genes within these and other significant QTL intervals, along with select genes known a priori to regulate telomere length, were tested for correlations between expression levels and telomere length in the IBM population and diverse inbred lines by quantitative real-time PCR. A slight but significant positive correlation between expression levels and telomere length was observed for many of the candidate genes, but Ibp2 was a notable exception, showing instead a negative correlation. A rad51-like protein (TEL-MD_5.04) was strongly supported as a candidate gene by several lines of evidence. Our results highlight the value of QTL mapping plus candidate gene expression analysis in a genetically diverse model system for telomere research.

Genetic Architecture of Natural Variation of Telomere Length inArabidopsis thaliana

“…Burr et al (1992) initially showed variation of telomere length within maize RIL populations (Burr et al 1992). QTL mapping in maize later identified a number of contributing loci and suggested a rad51-like protein as a candidate (Brown et al 2011). QTL from this study, however, are not confirmed experimentally with NILs, and candidates are selected from large QTL regions that are not fine-mapped.…”

Telomere Length in Plants Estimated with Long Read Sequencing

“…In shorter lived model plants and crops Arabidopsis thaliana, Oryza sativa (rice), and Zea mays (maize) telomere lengths are between 2-5 kb, 5-20 kb, and 6-25 kb respectively. In addition, there is variability among telomere lengths across different accessions within a species, while length is conserved within an accession (Shakirov and Shippen, 2004;Brown et al, 2011;Fulcher et al, 2015;Choi et al, 2021). Telomere length in plants has been associated with life history traits including seasonal and phenotypic variation, environmental interactions, sex, flowering time, and seed quantity (Liu et al, 2007;Mu et al, 2014;Choi et al, 2021;Osnato, 2021;Campitelli et al, 2022).…”

Application of Tris-HCl Allows the Specific Labeling of Regularly Prepared Chromosomes by CRISPR-FISH

“…In maize, only a subset of chromosomes showed telomere labeling. The maize line B73 has a short telomere size of approximately 2.3 kb [Brown et al, 2011]. In soybean, the telomere size ranges from 13 to 18 kb [Kolchinsky and Gresshoff, 1993].…”