Biology subjects

Hofer, J.

Publications and source records attributed to Hofer, J..

3 recordsLinked to original sources

bioRxiv2024

Genomic and Genetic Insights into Mendel's Pea Genes

Pea, Pisum sativum, is an excellent model system through which Gregor Mendel established the foundational principles of inheritance. Surprisingly, till today, the molecular nature of the genetic differences underlying the seven pairs of contrasting traits that Mendel studied in detail remains partially understood. Here, we present a genomic and phenotypic variation map, coupled with haplotype-phenotype association analyses across a wide range of traits in a global Pisum diversity panel. We focus on a genomics-enabled genetic dissection of each of the seven traits Mendel studied, revealing many previously undescribed alleles for the four characterized genes, R, Le, I and A, and elucidating the gene identities and mutations for the remaining three uncharacterized traits. Notably, we identify: (1) a ca. 100kb deletion upstream of the Chlorophyll synthase (ChlG) gene, which generates aberrant transcripts and confers the yellow pod phenotype of gp mutants; (2) an in-frame premature stop codon mutation in a Dodeca-CLE41/44 signalling peptide which explains the parchmentless mutant phenotype corresponding to p; and (3) a 5bp in-frame deletion in a CIK-like receptor kinase gene corresponding to the fasciated stem phenotype fa, which Mendel described in terms of flower position, and we postulate the existence of a Modifier of fa (Mfa) locus that masks this meristem defect. Mendel noted the pleiotropy of the a mutation, including inhibition of axil ring anthocyanin pigmentation, a trait we found to be controlled by allelic variants of the gene D within an R2R3-MYB gene cluster. Furthermore, we characterize and validate natural variation of a quantitative genetic locus governing both pod width and seed weight, characters that Mendel deemed were not sufficiently demarcated for his analyses. This study establishes a cornerstone for fundamental research, education in biology and genetics, and pea breeding practices.

genetics↗

bioRxiv2023

afila, the origin and nature of a major innovation in the history of pea breeding

The afila (af) mutation of Pisum sativum L. (pea) is characterised by leaves that are composed of a basal pair of stipules, a petiole and a branched mass of tendrils. These are bipinnate leaves in which the leaflet primordia are replaced by midrib-like, or terminal tendril, primordia. The phenotype was first reported as a spontaneous mutation in 1953, and several reports of spontaneously occurring af mutants and induced mutations have been published since then. Despite its wide-scale introgression to improve standing ability in combine-harvested dry pea crops, the molecular basis of af has remained unknown. Here, we show that the deletion of two tandemly-arrayed Q-type Cys(2)His(2)-zinc finger transcription factors, viz. PsPALM1a and PsPALM1b, is responsible for the af phenotype. Based on molecular evidence for the presence/absence of seven consecutive pea genes, we identified eight haplotypes in the genomic region of chromosome 2 that harbours af. These haplotypes differ in the presence or absence of PsPALM1a-b and close genes and in the size of the deletion. Representative cultivars and spontaneous or induced mutants were assigned to the different haplotypes. The hitherto unrecognised diversity at the af locus reveals highly rich, unexplored, potential for pea improvement and sheds light on the breeding history of pea. This knowledge can also be used to breed innovative cultivars in related crops.

genetics↗

bioRxiv2019

Barley RIC157 is involved in RACB-mediated susceptibility to powdery mildew

Successful obligate pathogens benefit from host cellular processes. For the biotrophic ascomycete fungus Blumeria graminis f.sp. hordei (Bgh) it has been shown that barley RACB, a small monomeric G-protein (ROP, RHO of plants), is required for full susceptibility to fungal penetration. The susceptibility function of RACB probably lies in its role in cell polarisation, which may be co-opted by the pathogen for invasive ingrowth of its haustorium. However, the actual mechanism of how RACB supports the fungal penetration success is little understood. RIC proteins (ROP-Interactive and CRIB-(Cdc42/Rac Interactive Binding) motif-containing) are considered scaffold proteins which can interact directly with ROPs via a conserved CRIB motif. Here we describe a yet uncharacterised RIC protein, RIC157, which can interact directly with RACB in planta. We show that RIC157 undergoes a recruitment from the cytoplasm to the cell periphery in the presence of activated RACB. During fungal infection, RIC157 and activated RACB colocalise at the penetration site, particularly at the haustorial neck. In a RACB-dependent manner, transiently overexpressed RIC157 renders barley epidermal cells more susceptible to fungal penetration. This suggests that RIC157 promotes fungal penetration into barley epidermal cells via its function downstream of RACB.

plant biology↗