Comparative Transcriptome Analysis Reveals the Effect of Lignin on Storage Roots Formation in Two Sweetpotato (Ipomoea batatas (L.) Lam.) Cultivars

Abstract

Sweet potato (Ipomoea batatas (L.) Lam.) is one of the most important crops with high storage roots yield. The formation and expansion rate of storage root (SR) plays a crucial role in the production of sweet potato. Lignin affects the SR formation; however, the molecular mechanisms of lignin in SR development have been lacking. To reveal the problem, we performed transcriptome sequencing of SR harvested at 32, 46, and 67 days after planting (DAP) to analyze two sweet potato lines, Jishu25 and Jishu29, in which SR expansion of Jishu29 was early and had a higher yield. A total of 52,137 transcripts and 21,148 unigenes were obtained after corrected with Hiseq2500 sequencing. Through the comparative analysis, 9577 unigenes were found to be differently expressed in the different stages in two cultivars. In addition, phenotypic analysis of two cultivars, combined with analysis of GO, KEGG, and WGCNA showed the regulation of lignin synthesis and related transcription factors play a crucial role in the early expansion of SR. The four key genes swbp1, swpa7, IbERF061, and IbERF109 were proved as potential candidates for regulating lignin synthesis and SR expansion in sweet potato. The data from this study provides new insights into the molecular mechanisms underlying the impact of lignin synthesis on the formation and expansion of SR in sweet potatoes and proposes several candidate genes that may affect sweet potato yield.

Genome-wide identification of the C2H2 zinc finger gene family and expression analysis under salt stress in sweetpotato

“…In order to study the expression patterns of IbZFP genes during SR expansion of sweetpotato, we used the transcriptome data of two different sweetpotato varieties at the early stage of SR expansion to analyze their expression levels ( Du et al., 2023 ).…”

“…Transcriptome data on SR expansion of two different varieties of sweetpotato from a previous study with NCBI project ID PRJNA756699, including J25_D1, J25_D2, J25_D3, J29_D1, J29_D2, and J29_D3 ( Du et al., 2023 ). In addition, transcriptome data of salt tolerant and salt sensitive sweetpotato varieties under salt stress were obtained from previous studies under NCBI project number PRJNA552932 ( Qin et al., 2020 ), including NL54_0 h, NL54_0.5 h, NL54_6 h, NL54_12 h, J26_0 h, J26_0.5 h, J26_6 h, and J26_12 h. The Chiplot online tool is used to generate heatmaps.…”

“…The sweetpotato planting area can reach 7.4 million hectares, with an annual production of about 88.9 million tonnes of storage roots (SRs). As the main edible tissue of sweetpotato, the production and development of SR are their most important agronomic traits ( Du et al., 2023 ). However, adverse abiotic factors like salt and drought severely restrict the sweetpotato plant’s growth, development, and output ( Zhang et al., 2023 ).…”

More or Less: Recent Advances in Lignin Accumulation and Regulation in Horticultural Crops

“…During the growth of Camellia oleifera shell, lignin content increased continuously, leading to a thickened stone cell wall [31]. By contrast, lignin content in storage root gradually decreased during the developmental stages in two sweet potato cultivars [32]. The concentrations of total lignin and its precursors displayed marked decreases during ginger tissue maturation; however, the lignin component was dramatically altered with syringyl lignin mainly enriched in mature rhizomes, contributing to ginger lignification [33].…”