The Opposite Roles of White Light in Regulating Germination of Fresh and Aged Seed in Tobacco

Abstract

Light is one of the important environmental factors for seeds to evaluate whether the natural environment is appropriate for germination and subsequent seedlings emergence. The mechanism of light-mediated germination is mainly concerned with fresh seeds (FS) of model plants but is poorly understood in aged seeds. Here, the effects of light on germination of FS and naturally aged seeds (NAS) in tobacco and their relationship with plant hormones gibberellins (GA) and abscisic acid (ABA) were investigated. The results demonstrated that light promoted and inhibited the germination of FS and NAS, respectively. GA and ABA were involved in the germination control of NAS, as well as in FS. However, light suppressed GA signal and stimulated ABA signal in NAS, whereas it stimulated GA signal and suppressed ABA signal in FS. In addition, light stimulated the GA accumulation and reduction in ABA in FS while inhibiting the increase in GA level in NAS. Together, the present study demonstrates that light has opposite effects on the germination of FS and NAS, which are closely related to the metabolism and/or signaling of plant hormones ABA and GA.

Systematic analysis of photo/sko-regulated germination and post-germination development of shallow photodormant seeds in Nicotiana tabacum L.

“…In this study, the expression of NtGAI and NtABI3 , 5 is suppressed by light ( Figure S13 ). Similar results were noticed in other photophilic-seeded species, such as lettuce ( Toyomasu et al., 1998 ; Sawada et al., 2008 ), and tobacco ( Wang et al., 2021 ; Dong et al., 2022 ).…”

“…NtABI3, 5 is suppressed by light (Figure S13). Similar results were noticed in other photophilic-seeded species, such as lettuce (Toyomasu et al, 1998;Sawada et al, 2008), and tobacco (Wang et al, 2021;Dong et al, 2022). Therefore, we believed that the light signaling pathway also plays a key regulatory role in the germination of shwallow photodormant seeds.…”

“…Germination of photophilic seeds promoted by light that had been reported in many species, such as Arabidopsis ( Borthwick et al., 1952 ; Shinomura et al., 1996 ; Hennig et al., 2001 ), Lactuca sativa Linn ( lettuce ) ( Toyomasu et al., 1998 ; Sawada et al., 2008 ), Nicotiana tabacum L (tobacco) ( Wang et al., 2021 ; Dong et al., 2022 ), and so on. In this study, we noticed shallow photodormant seeds have higher germination percentage and faster speed under light.…”

“…The expressions of genes required for cell wall loosening, such as EXP and XTH , are repressed to inhibit seed germination under dark in Arabidopsis ( Oh et al., 2009 ). The expression of NtXTH was upregulated by light to promote the germination of fresh seeds in tobacco ( Wang et al., 2021 ). The above studies suggest that light can promote the weakening of endosperm during seed germination by inducing the expression of genes involved in regulating cell wall hydrolysis.…”

Comparative Metabolomics Profiling Reveals Key Metabolites and Associated Pathways Regulating Tuber Dormancy in White Yam (<em>Dioscorea rotundata</em>)

“…Usually, upon dormancy induction some specific metabolites are accumulated and some signals activated to maintain low energy condition in yam tuber that characterize dormancy period, whereas, during dormancy breaking, varieties of metabolites and metabolisms are activated to provide nutrients and energy required for tuber dormancy breaking [7,45]. However, elucidating the key metabolites and metabolic pathways that regulate yam tuber dormancy, to the best of our knowledge has not been done previously, although the functions of some metabolites in botanical seeds have been established [32,[46][47][48]. Our study used untargeted metabolomics profiling to determine some key metabolites and their associated metabolic pathways that regulate yam tuber dormancy.…”