Identification of 5P Chromosomes in Wheat-Agropyron cristatum Addition Line and Analysis of Its Effect on Homologous Pairing of Wheat Chromosomes

Abstract

As an important wheat wild relative, the P genome of Agropyron cristatum (L.) Gaertn. (2n = 4x = 28) is very valuable for wheat improvement. A complete set of wheat-A. cristatum disomic addition lines is the basis for studying the genetic behavior of alien homoeologous chromosomes and exploring and utilizing the excellent genes. In this study, a wheat-A. cristatum derivative II-11-1 was proven to contain a pair of 5P chromosomes and a pair of 2P chromosomes with 42 wheat chromosomes by analyzing the fluorescence in situ hybridization (FISH) and expressed sequence tag (EST) markers. Additionally, cytological identification and field investigation showed that the 5P chromosome can weaken the homologous pairing of wheat chromosomes and promote the pairing between homoeologous chromosomes. This provides new materials for studying the mechanism of the alien gene affecting the homologous chromosome pairing and promoting the homoeologous pairing of wheat. In addition, chromosomal structural variants have been identified in the progeny of II-11-1. Therefore, the novel 5P addition line might be used as an important genetic material to widen the genetic resources of wheat.

Generation and identification of a wheat–Agropyron cristatum (L.) Gaertn. 3P chromosome addition line and substitution line

“…cristatum-derived lines I-27 and I-15 and wheat cultivar Fukuho were planted at the experimental farm of the Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Xinxiang, Henan Province, during the 2019-2020 and 2020-2021 growing seasons. The row length was 2.0 m, and the row spacing was 30 cm; each row contained 20 seeds (Pan et al 2022). Plant height, spike length, fertile tiller number, spikelet number, spikelet number per spike and grain number per spike were evaluated for each individual plant.…”

“…cristatum-derived lines, laying a foundation for wheat improvement by the use of these desirable genes. Among the exogenous addition lines and substitution lines containing the A. cristatum P chromosome that have been identified thus far, the 1P chromosome carries genes related to abiotic stress resistance and improved plant architecture (Pan et al 2017;Wang et al 2022); the 2P chromosome carries powdery mildew and leaf rust resistance genes (Li et al 2016;Jiang et al 2018); the 5P chromosome can promote partial homoeologous chromosome recombination (Pan et al 2022); the 6P chromosome can increase wheat yields by promoting the number of fertile spikelets per spike and final kernel number per spike (Wu et al 2006;Ye et al 2015); and the 7P chromosome carries grain weight-related gene(s) that positively regulate yield traits (Sun et al 2021). However, the excellent genes of the wheat-A.…”

Molecular evidence depicts genetic divergence among Agropyron elongatum and A. cristatum accessions from gene pool of Iran

“…Till now, wheat- A . cristatum 1P, 2P, 3P, 4P, 6P, and 7P disomic addition lines have been successfully created, and many excellent genes were located in specific chromosomes and transmitted into wheat [ 8 ]. For example, it has been found that the A .…”

“…Till now, wheat-A. cristatum 1P, 2P, 3P, 4P, 6P, and 7P disomic addition lines have been successfully created, and many excellent genes were located in specific chromosomes and transmitted into wheat [8]. For example, it has been found that the A. cristatum 6P addition line confers gene clusters related to yield, such as multiple florets and grains per spike, and the 2P addition line possesses gene clusters related to disease resistance, including powdery mildew, leaf rust, and stripe rust [9][10][11].…”