Biology subjects

Gadea, J.

Publications and source records attributed to Gadea, J..

2 recordsLinked to original sources

bioRxiv2022

Kaempferol over-accumulation in the flavonoid 3' hydroxylase tt7 mutant disrupts seed coat outer integument differentiation and compromises seed longevity

O_LISeeds slowly accumulate damage during storage, which ultimately results in germination failure. The seed coat is the barrier between the embryo and the external environment, and its composition is critical for seed longevity. Flavonols accumulates in the outer integument, but the effect of altering flavonol composition on outer integument development has not been explored. C_LIO_LIGenetic, biochemical, ultrastructural and transcriptomics assays on a battery of loss-of-function mutants in the flavonoid biosynthesis pathway were used to study the effect of altered flavonoid composition in seed development and seed longevity. C_LIO_LIControlled deterioration assays indicate that loss-of-function of the flavonoid 3 hydroxylase TT7 gene dramatically affects seed longevity and seed development. Seed outer integument differentiation is compromised from nine days after pollination in tt7 seeds, with a defective suberine layer and incomplete degradation of seed-coat starch. These distinctive phenotypes are not shared by other mutants showing also altered flavonoid composition. Double-mutant analysis indicate that over-accumulation of kaempferol is the primary cause of the observed phenotypes. Expression analysis suggest that the tt7 flavonoid pattern affects transcriptional and non-transcriptional levels of regulation. C_LIO_LIThe increase of kaempferols in the seed coat influences seed development. This positions TT7 as an essential player modulating seed coat development and seed longevity. C_LI

plant biology↗

bioRxiv2021

Comparative analysis of wild type accessions reveals novel determinants of Arabidopsis seed longevity

Understanding the genetic factors involved in seed longevity is of paramount importance in agricultural and ecological contexts. The polygenic nature of this trait suggests that many of them remain undiscovered. Here, we exploited the contrasting seed longevity found amongst wild type Arabidopsis thaliana accessions to further understand this phenomenon. Concentrations of the antioxidant glutathione were consistently higher in longer-lived than shorter-lived accessions, supporting that redox poise plays a prominent role in seed longevity. However, high seed permeability, normally associated with shorter longevity, is also present in accessions with longer seed longevity. Transcriptome analysis indicated that the detrimental effect on longevity caused by seed coat permeability may be counterbalanced by higher levels of specific mRNAs stored in dry seed, particularly those of heat-shock proteins. Indeed, reverse genetics demonstrated that heat-shock factors HSF1A and 1B contributed to longevity. Furthermore, loss-of-function mutants of RNA-binding proteins, such as the stress-granule zinc-finger protein TZF9, or the spliceosome subunits MOS4 or MAC3A/MAC3B, extended seed longevity, positioning RNA as a novel player in the regulation of seed viability. mRNAs of proteins with putative relevance to longevity were also abundant in shorter-lived accessions, reinforcing the idea that resistance to ageing is determined by multiple factors.

plant biology↗