Biology subjects

Alenazi, A. S.

Publications and source records attributed to Alenazi, A. S..

2 recordsLinked to original sources

bioRxiv2025

Gene turnover and contingency facilitated the repeated evolution of C4 photosynthesis in grasses

SummaryO_LIIn grasses, almost all species belong to two evenly sized clades (BOP and PACMAD), yet the >20 independent origins of C4 photosynthesis in this family only occur in the PACMAD lineage. Here, we identify potential genetic precursors for C4 photosynthesis that were present at the base of the PACMAD clade, representing the last common ancestor of all C4 grasses. C_LIO_LIWe generated the first reference genomes for Aristidoideae species (Aristida adscensionis and Stipagrostis hirtigluma), the sister lineage of all other PACMAD grasses. In combination with 34 other Poales genomes, we identify gene gains at the base of the PACMAD clade, and genes lost in the sister BOP lineage. C_LIO_LICandidate C4 precursors include {beta}-carbonic anhydrase, as well as genes involved in amino acid and nitrate transport, carbon metabolism, oxidative stress management and transcription regulation. C_LIO_LIGene turnover created the necessary genetic contingency, facilitating the independent recruitment and refinement of C4 genes in multiple independent origins. Our results support the idea that the repeated evolution of C4 photosynthesis in PACMAD grasses was not driven by a single genetic event but was instead underwritten by chance genetic changes that originated long before there was selection for the trait itself. C_LI

evolutionary biology↗

bioRxiv2024

Identifying leaf anatomy and metabolic regulators that underpin C4 photosynthesis in Alloteropsis semialata

O_LIC4 photosynthesis is a complex trait requiring multiple developmental and metabolic alterations. Despite this complexity, it has independently evolved over 60 times. However, our understanding of the transition to C4 is complicated by the fact that variation in photosynthetic type is usually segregated between species. C_LIO_LIHere, we perform a genome wide association study (GWAS) using the grass Alloteropsis semialata, the only known species to have C3, intermediate, and C4 accessions. We aimed to identify genomic regions associated with the strength of the C4 cycle (measured using {delta}13C), and the development of C4 leaf anatomy. C_LIO_LIGenomic regions correlated with {delta}13C include regulators of C4 decarboxylation enzymes (RIPK), non-photochemical quenching (SOQ1), and the development of Kranz anatomy (SCARECROW-LIKE). Regions associated with the development of C4 leaf anatomy in the intermediate accessions contain additional leaf anatomy regulators, including those responsible for vein patterning (GSL8) and meristem determinacy (GRF1). C_LIO_LIThe detection of highly correlated genomic regions with a modest sample size indicates that the emergence of C4 photosynthesis in A. semialata required a few loci of large effect. The candidate genes could prove to be relevant for engineering C4 leaf anatomy in C3 species. C_LI

plant biology↗