One Way to Achieve Germination: Common Molecular Mechanism Induced by Ethylene and After-Ripening in Sunflower Seeds

Abstract

Dormancy is an adaptive trait that blocks seed germination until the environmental conditions become favorable for subsequent vegetative plant growth. Seed dormancy is defined as the inability to germinate in favorable conditions. Dormancy is alleviated during after-ripening, a dry storage period, during which dormant (D) seeds unable to germinate become non-dormant (ND), able to germinate in a wide range of environmental conditions. The treatment of dormant seeds with ethylene (D/ET) promotes seed germination, and abscisic acid (ABA) treatment reduces non-dormant (ND/ABA) seed germination in sunflowers (Helianthus annuus). Metabolomic and transcriptomic studies have been performed during imbibition to compare germinating seeds (ND and D/ET) and low-germinating seeds (D and ND/ABA). A PCA analysis of the metabolites content showed that imbibition did not trigger a significant change during the first hours (3 and 15 h). The metabolic changes associated with germination capacity occurred at 24 h and were related to hexoses, as their content was higher in ND and D/ET and was reduced by ABA treatment. At the transcriptional level, a large number of genes were altered oppositely in germinating, compared to the low-germinating seeds. The metabolomic and transcriptomic results were integrated in the interpretation of the processes involved in germination. Our results show that ethylene treatment triggers molecular changes comparable to that of after-ripening treatment, concerning sugar metabolism and ABA signaling inhibition.

Whole‐genome resequencing‐based QTL‐seq identified candidate genes and molecular markers for fresh seed dormancy in groundnut

“…There are several sequencingbased trait-mapping approaches which provide faster discovery of candidate genes and facilitate marker development; and one of such approach for trait mapping is QTL-seq (Pandey et al, 2017;Takagi et al, 2013). It has been successfully deployed in several important crop species for trait dissection such as rice blast disease (Takagi et al, 2013), grain length and weight in rice (Yaobin et al, 2018), flowering time in tomato (Ruangrak et al, 2018), foliar disease resistance (Clevenger et al, 2018;Pandey et al, 2017), shelling percentage (Luo et al, 2019a) and bacterial wilt resistance (Luo et al, 2019b) in groundnut, 100 seed weight and root/total plant dry weight in chickpea (Singh et al, 2016a), plant height in soybean (Zhang et al, 2018), etc. Many of these efforts facilitated successful development of diagnostic markers which are being deployed in GAB.…”

“…Likewise, a 0.74-Mb SNP-enriched genomic region was identified on the pseudomolecule A09 of A-subgenome, containing a nonsynonymous SNP on an ABA biosynthetic gene zeaxanthin epoxidase (ZEP, Aradu.D94AQ). Further, this genomic appeared as one of the key controllers of ABA biosynthesis in groundnut as this genomic region is home to several important genes which are known to participate in ABA signalling and control seed dormancy such as PPR superfamily protein gene, protein phosphatase 2C/2A family protein gene, GRAM domain protein/ABA-responsive-like and serine carboxypeptidase 46 (Mauri et al, 2016;N ee et al, 2017;Xia et al, 2018).…”

A Correlative Study of Sunflower Seed Vigor Components as Related to Genetic Background

“…The analysis allowed the distribution of genotypes with a high PCA percentage (74,68%) in seven clusters corresponding to marked resistance or sensitivity to one or several stresses (Figure 4, Table 3). The cluster 5 contained an important number of genotypes (17), which did not show a marked response to extreme conditions ( Table 3). In the other clusters, genotypes displayed contrasted responses.…”

“…The genetic basis of seed vigor has been established, although it is poorly understood [10]. In the last decades, molecular aspects of seed dormancy and germination have been reported in different species (for review [11][12][13]) and in sunflower in particular [14][15][16][17]. Several genes have been related to seed vigor [18][19][20], but, they can hardly be used as vigor genetic markers.…”

Activation of plasma membrane H+-ATPases participates in dormancy alleviation in sunflower seeds

“…Abscisic acid (ABA) is a positive regulator of dormancy and a negative regulator of seed germination while other hormones such as gibberellins (GA) or ethylene (ET) promote germination completion by antagonising ABA effects [4,2,5,6]. In sunflower, ET is the major hormone acting as an antagonist of ABA and a positive regulator of seed germination [7][8][9]. In seeds, ROS and ABA have antagonistic effects [10,11], and ROS produced during soybean seed imbibition could promote ET production [12] and conversely, ET induced ROS accumulation in sunflower seeds [1].…”