Assessment of genetic diversity and variety identification based on developed retrotransposon-based insertion polymorphism (RBIP) markers in sweet potato (Ipomoea batatas (L.) Lam.)

Abstract

Sweet potato, a dicotyledonous and perennial plant, is the third tuber/root crop species behind potato and cassava in terms of production. Long terminal repeat (LTR) retrotransposons are highly abundant in sweet potato, contributing to genetic diversity. Retrotransposon-based insertion polymorphism (RBIP) is a high-throughput marker system to study the genetic diversity of plant species. To date, there have been no transposon marker-based genetic diversity analyses of sweet potato. Here, we reported a structure-based analysis of the sweet potato genome, a total of 21555 LTR retrotransposons, which belonged to the main LTR-retrotransposon subfamilies Ty3-gypsy and Ty1-copia were identified. After searching and selecting using Hidden Markov Models (HMMs), 1616 LTR retrotransposon sequences containing at least two models were screened. A total of 48 RBIP primers were synthesized based on the high copy numbers of conserved LTR sequences. Fifty-six amplicons with an average polymorphism of 91.07% were generated in 105 sweet potato germplasm resources based on RBIP markers. A Unweighted Pair Group Method with Arithmatic Mean (UPGMA) dendrogram, a model-based genetic structure and principal component analysis divided the sweet potato germplasms into 3 groups containing 8, 53, and 44 germplasms. All the three analyses produced significant groupwise consensus. However, almost all the germplasms contained only one primary locus. The analysis of molecular variance (AMOVA) among the groups indicated higher intergroup genetic variation (53%) than intrapopulation genetic variation. In addition, long-term self-retention may cause some germplasm resources to exhibit variable segregation. These results suggest that these sweet potato germplasms are not well evolutionarily diversified, although geographic speciation could have occurred at a limited level. This study highlights the utility of RBIP markers for determining the intraspecies variability of sweet potato and have the potential to be used as core primer pairs for variety identification, genetic diversity assessment and linkage map construction. The results could provide a good theoretical reference and guidance for germplasm research and breeding.

Phenotypic variability and genetic diversity analysis of cultivated potatoes in China

“…Cluster analysis has been widely used for classifying plant genetic material. Dendrograms of the cluster analysis based on morphological and physiological traits for rice (Verma et al, 2019), tomato (Ayenan et al, 2021) and sweet potato (Meng et al, 2021). In this study, most traits of 149 cultivars showed significant differences.…”

Retrotransposons: How the continuous evolutionary front shapes plant genomes for response to heat stress

“…The development of Retrotransposon-Based Insertion Polymorphism (RBIP) markers (Flavell et al, 1998) derived from sweet potatoes can determine intraspecific variability. These markers can also be used as core primer pairs for evaluating genetic diversity and constructing linkage maps of various plant species, guiding breeding and germplasm research (Meng et al, 2021). The RBIP marker was shown to be duplicated several times during the development of Asian pear cultivars and may provide a comprehensive picture of the complex relationship and evolution of Pyrus species (Jiang et al, 2015).…”

Molecular characterization of sweet potato (Ipomoea batatas [L.] Lam) germplasms for desirable traits by using simple sequence repeats markers

“…Sweet potatoes may also be used for animal feed, starch extraction, alcohol, and biofuel. Many poor nations might benefit from the high concentration of β-carotene in these orange-fleshed sweet potatoes, which could help avoid blindness and maternal mortality caused by vitamin A insufficiency (Meng et al, 2021).…”