Transcriptome and Metabolite Conjoint Analysis Reveals the Seed Dormancy Release Process in Callery Pear

Abstract

Seed dormancy transition is a vital developmental process for seedling propagation and agricultural production. The process is precisely regulated by diverse endogenous genetic factors and environmental cues. Callery pear (Pyrus calleryana Decne) is an important rootstock species that requires cold stratification to break seed dormancy, but the mechanisms underlying pear seed dormancy release are not yet fully understood. Here, we analyzed the transcriptome profiles at three different stages of cold stratification in callery pear seeds using RNA sequencing combined with phytohormone and sugar content measurements. Significant alterations in hormone contents and carbohydrate metabolism were observed and reflected the dormancy status of the seeds. The expressions of genes related to plant hormone metabolism and signaling transduction, including indole-3-acetic acid (IAA) biosynthesis (ASAs, TSA, NITs, YUC, and AAO) genes as well as several abscisic acid (ABA) and gibberellic acid (GA) catabolism and signaling transduction genes (CYP707As, GA2ox, and DELLAs), were consistent with endogenous hormone changes. We further found that several genes involved in cytokinin (CTK), ethylene (ETH), brassionolide (BR), and jasmonic acid (JA) metabolism and signaling transduction were differentially expressed and integrated in pear seed dormancy release. In accordance with changes in starch and soluble sugar contents, the genes associated with starch and sucrose metabolism were significantly up-regulated during seed dormancy release progression. Furthermore, the expression levels of genes involved in lipid metabolism pathways were also up-regulated. Finally, 447 transcription factor (TF) genes (including ERF, bHLH, bZIP, NAC, WRKY, and MYB genes) were observed to be differentially expressed during seed cold stratification and might relate to pear seed dormancy release. Our results suggest that the mechanism underlying pear seed dormancy release is a complex, transcriptionally regulated process involving hormones, sugars, lipids, and TFs.

Integrating Transcriptomics and Hormones Dynamics Reveal Seed Germination and Emergence Process in Polygonatum cyrtonema Hua

“…ABA levels are closely related to seed dormancy status. In this study, ABA levels showed a significant decline during the germination process ( Figure 2 ), which was similar to that of red bayberry [ 15 ], celery [ 16 ], ginkgo [ 17 ], and pear [ 18 ]. Concomitantly, the expression profiles of multiple ABA biosynthesis and deactivation genes, including NCEDs and CYP707As, were highly consistent with the dynamics of ABA ( Figure 2 ).…”

“…The specific role of IAA in seed germination may vary between species. Some studies have reported that IAA levels increase during seed imbibition and after ripening in Arabidopsis , pear [ 18 ], and wheat [ 26 ]; on the contrary, more studies have implied that IAA acts through interaction with ABA and thereby inhibits seed germination and pre-harvest sprouting instead of promoting seed dormancy [ 26 ]. In the present study, the trend in IAA content was similar to that of ABA content, which decreased from DS to ES.…”

A preliminary mapping of QTL qsg5.1 controlling seed germination in melon (Cucumis melo L.)

“…The chromosome 8 QTL 2021-qsg8.1 is located between 1,742,525 and1,779,289 bp, a 36.26 Kb region that contains six functional genes. Among them, a potential candidate is a NAC domain-containing protein, which is well-known in plant growth, particularly in seed germination and dormancy (Mathew et al, 2016 ; Kong et al, 2020 ; Zhang et al, 2022c ). Other potential candidate genes, such as the receptor-like protein kinase HSL1, were also located in the region.…”

Transcriptome and proteome analyses reveal the potential mechanism of seed dormancy release in Amomum tsaoko during warm stratification

“…Some studies suggest that the duration of stratification also affects seed dormancy release. The seed germination rate of pear rapidly increased and reached 85% after 50 days of cold stratification [6]. Moreover, a study of Paris polyphylla showed that seed dormancy release during warm stratification is controlled not only by the temperature but also by the duration of stratification [7], indicating that seed dormancy release is precisely regulated by temperature and time.…”

“…In dormant Arabidopsis seeds, alternating temperatures can break dormancy by increasing the expression of GA3ox1 mediated through phytochrome B [12]. Meanwhile, the transcription factors (TFs) ERF, MYB, bHLH, NAC, WRKY, and MADS play important roles in the seed dormancy release of pear during cold stratification [6]. Additionally, the transcription factor ABA INSENSITIVE4 (ABI4) affects the seed dormancy status by targeting genes related to ABA and GA biosynthesis, catabolism, and signal transduction [13,14].…”