B-Box transcription factor BBX28 requires CONSTITUTIVE PHOTOMORPHOGENESIS1 to induce shade-avoidance response in Arabidopsis thaliana.

Shade avoidance syndrome is an important adaptive strategy. Under shade, major transcriptional rearrangements underlie the reallocation of resources to elongate vegetative structures and redefine the plant architecture to compete for photosynthesis. BBX28 is a B-box transcription factor involved in seedling de-etiolation and flowering in Arabidopsis (Arabidopsis thaliana), but its function in shade-avoidance response is completely unknown.

A tomato B-box protein regulates plant development and fruit quality through the interaction with PIF4, HY5, and RIN transcription factors.

During the last decade, knowledge about BBX proteins has greatly increased. Genome-wide studies identified the BBX gene family in several ornamental, industry, and food crops; however, reports regarding the role of these genes as regulators of agronomically important traits are scarce. Here, by phenotyping a knockout mutant, we performed a comprehensive functional characterization of the tomato locus Solyc12g089240, hereafter called SlBBX20.

Unveiling Molecular Signatures in Light-Induced Seed Germination: Insights from PIN3, PIN7, and AUX1 in .

Light provides seeds with information that is essential for the adjustment of their germination to the conditions that are most favorable for the successful establishment of the future seedling. The promotion of germination depends mainly on environmental factors, like temperature and light, as well as internal factors associated with the hormonal balance between gibberellins (GA) and abscisic acid (ABA), although other hormones such as auxins may act secondarily. While transcriptomic studies of light-germinating seeds suggest that auxins and auxin transporters are necessary, there are still no functional studies connecting the activity of the auxin transporters in light-induced seed germination.

BBX24 Interacts with JAZ3 to Promote Growth by Reducing DELLA Activity in Shade Avoidance.

Shade avoidance syndrome (SAS) is a strategy of major adaptive significance and typically includes elongation of the stem and petiole, leaf hyponasty, reduced branching and phototropic orientation of the plant shoot toward canopy gaps. Both cryptochrome 1 and phytochrome B (phyB) are the major photoreceptors that sense the reduction in the blue light fluence rate and the low red:far-red ratio, respectively, and both light signals are associated with plant density and the resource reallocation when SAS responses are triggered. The B-box (BBX)-containing zinc finger transcription factor BBX24 has been implicated in the SAS as a regulator of DELLA activity, but this interaction does not explain all the observed BBX24-dependent regulation in shade light.

Post-transcriptional regulation of seed dormancy and germination: Current understanding and future directions.

Seed dormancy is a developmental checkpoint that prevents mature seeds from germinating under conditions that are otherwise favorable for germination. Temperature and light are the most relevant environmental factors that regulate seed dormancy and germination. These environmental cues can trigger molecular and physiological responses including hormone signaling, particularly that of abscisic acid and gibberellin.

ATHB2 is a negative regulator of germination in Arabidopsis thaliana seeds.

The germination timing of seeds is of the utmost adaptive importance for plant populations. Light is one of the best characterized factors promoting seed germination in several species. The germination is also finely regulated by changes in hormones levels, mainly those of gibberellin (GA) and abscisic acid (ABA).

Alternative Splicing Regulation During Light-Induced Germination of Seeds.

Seed dormancy and germination are relevant processes for a successful seedling establishment in the field. Light is one of the most important environmental factors involved in the relief of dormancy to promote seed germination. In seeds, phytochrome photoreceptors tightly regulate gene expression at different levels.

Physiological and molecular mechanisms underlying the integration of light and temperature cues in Arabidopsis thaliana seeds.

The relief of dormancy and the promotion of seed germination are of extreme importance for a successful seedling establishment. Although alternating temperatures and light are signals promoting the relief of seed dormancy, the underlying mechanisms of their interaction in seeds are scarcely known. By exposing imbibed Arabidopsis thaliana dormant seeds to two-day temperature cycles previous of a red light pulse, we demonstrate that the germination mediated by phytochrome B requires the presence of functional PSEUDO-RESPONSE REGULATOR 7 (PRR7) and TIMING OF CAB EXPRESSION 1 (TOC1) alleles.

Phytochrome B increases drought tolerance by enhancing ABA sensitivity in Arabidopsis thaliana.

Phytochrome B (phyB) can adjust morphological and physiological responses according to changes in the red:far-red (R:FR) ratio. phyB-driven acclimation of plants to open environments (high R:FR ratio) increases carbon gain at the expense of increased water loss. This behaviour alleviates stressful conditions generated by an excess of light, but increases the chances of desiccation.

Gene expression analysis of light-modulated germination in tomato seeds.

Tomato (Solanum lycopersicum) seed germination can be inhibited by continuous irradiation with far-red light (FRc) and re-induced by a subsequent red light pulse. In this study, we carried out a global transcript analysis of seeds subjected to FRc inhibitory treatment, with and without a subsequent red light pulse, using potato cDNA microarrays. We also identified and characterized genes involved in light-modulated germination as elements of the phytochrome signalling pathway.

Impact of solar UV-B radiation on seedling emergence, chlorophyll fluorescence, and growth and yield of radish (Raphanus sativus).

We report the impact of present-day solar UV-B radiation on seedling emergence, its association with the accumulation of UV-absorbing compounds, and the growth and yield of radish (Raphanus sativus L.). Two field experiments were conducted at intermediate latitudes in South America (Buenos Aires, Argentina) using two cultivars of radish (`Scarlet Globe' and `Sparkler National').