Biology subjects

Serret, J.

Publications and source records attributed to Serret, J..

4 recordsLinked to original sources

bioRxiv2026

Connecting gene expression and cytokinin signaling during meristem determinacy transition in the rice panicle

Structural complexity in the rice inflorescence (panicle) is determined by the activity of indeterminate meristems, which allow sequential branching events to occur but later acquire a determinate character that precludes the initiation of new growth axes. To better understand the underlying regulatory processes, we combined a detailed time-course of panicle development with tissue-specific sampling of meristems before and after the determinacy switch, monitoring global gene expression programs and hormone accumulation. This allowed the delineation of three dynamic transcriptional modules and the inference of gene regulatory networks highlighting hormone regulatory hubs associated with the indeterminate-to-determinate meristem transition. Our data confirm the importance of known regulators of inflorescence development and identify novel actors, notably genes encoding transcription factors, that were not previously described in the regulation of flowering. The combined biochemical and transcriptomic data support a model in which cytokinin signalling is particularly active during the proliferative branching phase, during which meristem maintenance is promoted while a feedback mechanism is also triggered, ultimately leading to the acquisition of determinate meristem fate later in development. HighlightInvestigating the molecular nature of rice inflorescence meristem determinacy, we studied temporal and spatial gene expression alongside hormone accumulation, identifying novel regulatory interactions and a key role for cytokinins.

plant biology↗

bioRxiv2024

Gene coexpression network analysis of galactomannan biosynthesis and endosperm maturation in species of the genus Coffea

In a few important plant families and genera, including Arecaceae, Fabaceae and the genus Coffea, the main seed storage polysaccharide is not starch but cell wall galactomannans. Such seeds are albuminous with a persistent copious living endosperm that accumulates galactomannans. However, our understanding of the regulation of endosperm maturation, cell wall formation and galactomannan biosynthesis in albuminous seeds remains very limited. To gain insights into these processes, a large RNA-seq dataset was produced (14 coffee species x 5 endosperm developmental stages) and scrutinized using gene coexpression network analysis. The network revealed tight transcriptional coordination of the core galactomannan biosynthetic machinery for sucrose import, glycolysis, nucleotide sugar synthesis and transport, arabinogalactan protein and cellulose synthesis, and regulation of the trans-Golgi network. The orchestration of galactomannan and oil accumulation during endosperm maturation appeared to be exerted by the transcription factors FUSCA3, WRINKLED1, SHINE2 and DREB2D. The latter was the only coexpression partner of galactomannan biosynthetic genes. Numerous key genes of galactomannan biosynthesis were significantly upregulated in coffee somatic embryos overexpressing DREB2D, which showed increased production of UDP-galactose and diversion towards raffinose family oligosaccharides. Further, most genes of the galactomannan coexpression module were identified as DREB2D target genes by DAP-seq analysis. HighlightGene coexpression network analysis of the maturing endosperm identified the AP2/ERF transcription factor DREB2D as a major regulator of galactomannan accumulation in the cell walls of albuminous coffee seeds.

plant biology↗

bioRxiv2024

Picturing plant biodiversity from airborne environmental DNA.

While eDNA approaches have gained interest over the past decades all types of organisms have not been addressed evenly. In particular terrestrial plants have been the subject of less attention. Here we address the possibility to represent plant biodiversity from airborne environmental DNA (eDNA) sampling and metabarcoding. We collected air using a biological air sampler in the Botanical Garden of Montpellier (France) and compared the list of revealed plant species to the botanical inventory of the Garden. Ninety-two plant species could be detected from three sampling points across the 4,6 ha of the Garden, after one hour sampling allowing to filter 9 m3 of air. We recorded the plants carrying flowers at the time of the experiment, which allowed us to estimate that plants flowering at the time of the sampling could be detected 10 times more easily than plants that were not, given the number of plants carrying flowers. However, flowering is far from being required as a vast majority of plants still was detected without flowering. We also show that not all species orders are detected with the same probability, tree species being better represented in the sample than herbal plants, given the number of trees present in the garden. Finally using diagnostic species, present only once in the garden, we estimate that the maximum sampling distance allowed by the biological air sampler is at least 110 m. Our study underlines that air sampling is a promising method for monitoring terrestrial plant biodiversity and highlights the parameters that should be adjusted to optimize the approach.

genetics↗

bioRxiv2023

African rice (Oryza glaberrima) genomic introgressions impacting upon panicle architecture in Asian rice (O. sativa) lead to the identification of key QTLs

BackgroundDeveloping high yielding varieties is a major challenge for breeders tackling the challenges of climate change in agriculture. The panicle (inflorescence) architecture of rice is one of the key components of yield potential and displays high inter- and intra-specific variability. The genus Oryza features two different crop species: Asian rice (Oryza sativa L.) and the African rice (O. glaberrima Steud). One of the main morphological differences between the two independently domesticated species is the structure (or complexity) of the panicle, with O. sativa displaying a highly branched panicle, which in turn produces a larger number of grains than that of O. glaberrima. The genetic interactions that govern the diversity of panicle complexity within and between the two species are still poorly understood. ResultsTo identify genetic factors linked to panicle architecture diversity in the two species, we used a set of 60 Chromosome Segment Substitution Lines (CSSLs) issued from third generation backcross (BC3DH) and carrying genomic segments from O. glaberrima cv. MG12 in the genetic background of O. sativa Tropical Japonica cv. Caiapo. Phenotypic data were collected for rachis and primary branch length, primary, secondary and tertiary branch number and spikelet number. A total of 15 QTLs were localized on chromosomes 1, 2, 3, 7, 11 and 12 and QTLs associated with enhanced secondary and tertiary branch numbers were detected in two CSSLs. Furthermore, BC4F3:5 lines carrying different combinations of substituted segments were produced to decipher the effects of the identified QTL regions on variations in panicle architecture. A detailed analysis of phenotypes versus genotypes was carried out between the two parental genomes within these regions in order to understand how O. glaberrima introgression events may lead to alterations in panicle traits. ConclusionOur analysis led to the detection of genomic variations between O. sativa cv. Caiapo and O. glaberrima cv. MG12 in regions associated with enhanced panicle traits in specific CSSLs. These regions contain a number of key genes that regulate panicle development in O. sativa and their interspecific genomic variations may explain the phenotypic effects observed.

plant biology↗