Identification and Expression Analysis of the Goji Haploid-Inducible Gene DMP

Goji, a plant unique to China, is recognized for its dual use as both a food and a medicine and is rich in various nutrients. However, long-term asexual propagation often leads to cultivar degeneration and viral accumulation, which severely impact its yield, quality, and disease resistance. Homozygous seeds can stably produce offspring with uniform traits. Haploid breeding technology, which involves doubling the chromosomes of haploid plants to obtain homozygous diploids, can significantly accelerate the breeding process. The DMP (Domain of Unknown Function 679 Membrane Protein) family is a plant-specific family of membrane proteins involved in various biological functions, including physiological processes, reproductive development, and senescence. Concurrently, loss-of-function of the DMP gene impedes the proper integration of the paternal genome following fertilization. Consequently, the embryo develops with exclusively maternal chromosomes, a mechanism that underlies the induction of haploids. In this study, we conducted a genome-wide identification of the DMP gene family in goji, analyzing the physicochemical properties, chromosomal locations, cis-acting elements, phylogenetic relationships, sequence characteristics, expression patterns, and subcellular localization of its members. The objective was to identify DMP genes capable of inducing haploid production in goji berry for future breeding applications. The results revealed a total of 11 DMP family members in the goji berry genome, distributed across seven chromosomes. The proteins encoded by these members contain 136 to 237 amino acids, with molecular weights ranging from 15,267.96 to 26,141.01 Da and isoelectric points (pI) ranging from 5.14 to 9.32. The LbDMPs were found to contain numerous cis-acting elements that play roles in plant responses to abiotic stresses and various phytohormones. Notably, LbDMP1 and LbDMP11, which contain the typical DUF679 domain, are predominantly expressed in pollen, suggesting their involvement in the reproductive process of goji berry. They were therefore identified as candidate genes for haploid induction. Subcellular localization analysis demonstrated that LbDMP1 is localized to the plasma membrane, while LbDMP11 is localized to membrane systems such as the endoplasmic reticulum. This research provides a fundamental basis for further exploration of the functional roles of the DMP gene family in goji berry and offers valuable genetic resources for haploid induction in its breeding programs.