bims-plasge 2020-02-16 papers

G3 (Bethesda). 2020 Feb 11. pii: g3.401091.2020. [Epub ahead of print]

Genetic Analysis and Fine Mapping of a Spontaneously Mutated Male Sterility Gene in Brassica rapa ssp. chinensis.

Male sterility has been widely used in hybrid seed production in Brassica, but not in B. rapa ssp. chinensis, and genetic models of male sterility for this subspecies are unclear. We discovered a spontaneous mutant in B. rapa ssp. chinensis A series of progeny tests indicated that male sterility in B. rapa ssp. chinensis follows a three-allele model with BrMsa , BrMsb , and BrMsc. The male sterility locus has been mapped to chromosome A07 in BC1 and F2 populations through genotyping by sequencing. Fine mapping in a total of 1,590 F2 plants narrowed the male sterility gene BrMs to a 400 kb region, with two SNP markers only 0.3 cM from the gene. Comparative gene mapping shows that the Ms gene in B. rapa ssp. pekinensis is different from the BrMs gene of B. rapa ssp. chinensis, despite that both genes are located on chromosome A07. Interestingly, the DNA sequence orthologous to a male sterile gene in Brassica napus, BnRf, is within 400 kb of the BrMs locus. The BnRf orthologs of B. rapa ssp. chinensis were sequenced, and one KASP marker (BrMs_indel) was developed for genotyping based on a 14 bp indel at intron 4. Cosegregation of male sterility and BrMs_indel genotypes in the F2 population indicated that BnRf from B. napus and BrMs from B. rapa are likely to be orthologs. The BrMs_indel marker developed in this study will be useful in marker-assisted selection for the male sterility trait.

Keywords: SNP; genic male sterility; genotyping by sequencing (GBS); mutant; non-heading Chinese cabbage; plant breeding

DOI: https://doi.org/10.1534/g3.120.401091

Nat Plants. 2020 Feb 13.

Integration of ovular signals and exocytosis of a Ca2+ channel by MLOs in pollen tube guidance.

Jiang-Guo Meng, Liang Liang, Peng-Fei Jia, Ying-Chun Wang, Hong-Ju Li, Wei-Cai Yang.

The spatiotemporal regulation of Ca2+ channels at the plasma membrane in response to extracellular signals is critical for development, stress response and reproduction, but is poorly understood. During flowering-plant reproduction, pollen tubes grow directionally to the ovule, which is guided by ovule-derived signals and dependent on Ca2+ dynamics. However, it is unknown how ovular signals are integrated with cytosolic Ca2+ dynamics in the pollen tube. Here, we show that MILDEW RESISTANCE LOCUS O 5 (MLO5), MLO9 and MLO15 are required for pollen tube responses to ovular signals in Arabidopsis thaliana. Phenotypically distinct from the ovule-bypass phenotype of previously identified mutants, mlo5 mlo9 double-mutant and mlo5 mlo9 mlo15 triple-mutant pollen tubes twist and pile up after sensing the ovular cues. Molecular studies reveal that MLO5 and MLO9 selectively recruit Ca2+ channel CNGC18-containing vesicles to the plasma membrane through the R-SNARE proteins VAMP721 and VAMP722 in trans mode. This study identifies members of the conserved seven transmembrane MLO family (expressed in the pollen tube) as tethering factors for Ca2+ channels, reveals a novel mechanism of molecular integration of extracellular ovular cues and selective exocytosis, and sheds light on the general regulation of MLO proteins in cell responses to environmental stimuli.

DOI: https://doi.org/10.1038/s41477-020-0599-1

J Proteome Res. 2020 Feb 10.

Quantitative Analysis of Target Peptides Related to Resistance Against Ascochyta Blight (Peyronellaea pinodes) in Pea.

María-Ángeles Castillejo, Sara Fondevilla-Aparicio, Carlos Fuentes-Almagro, Diego Rubiales.

Peyronellaea pinodes causes Ascochyta blight, one of the major diseases in pea worldwide. Cultivated pea plants have a low resistance to this disease. Although quantitative trait loci (QTLs) involved in the resistance to Ascochyta blight have been identified, the specific genes associated with these QTLs remain unknown, which makes marker-assisted selection difficult. Complex traits alter proteins and their abundance. Quantitative estimation of proteins in pea might therefore be useful in selecting potential markers for breeding. In this work, we developed a strategy using a combination of shotgun proteomics (viz., high performance liquid chromatography-mass spectrometry data-dependent acquisition) and data-independent acquisition (DIA) analysis, to identify putative protein markers associated with resistance to Ascochyta blight and explored its use for breeding selection. For this purpose, an initial list of target peptides based on proteins closely related to resistance to P. pinodes was compiled by using two genotypes with contrasting responses to the disease. Then, targeted data analysis (viz., shotgun proteomics-DIA) was used for constitutive quantification of the target peptides in a representative number of the recombinant inbred line population segregated for resistance as derived from a cross between the two genotypes. Finally, a peptide panel of potential markers for resistance to P. pinodes was built. The results thus obtained are discussed and compared with those of previous gene expression studies using the same parental pea genotypes responding to the pathogen. Also, a molecular defense mechanism against Ascochyta blight in pea is proposed. To the authors' knowledge, this is the first time a targeted proteomics approach based on data analysis has been used to identify peptides associated with resistance to this disease.

Keywords: Ascochyta blight; data-independent acquisition (DIA); pea; peptide markers; resistance; shotgun-data-dependent acquisition (DDA); targeted proteomics analysis

DOI: https://doi.org/10.1021/acs.jproteome.9b00365

Biochim Biophys Acta Mol Cell Res. 2020 Feb 07. pii: S0167-4889(20)30033-1. [Epub ahead of print] 118675

The diversity of ACBD proteins - From lipid binding to protein modulators and organelle tethers.

Markus Islinger, Joseph L Costello, Suzan Kors, Eric Soupene, Timothy P Levine, Frans A Kuypers, Michael Schrader.

Members of the large multigene family of acyl-CoA binding domain containing proteins (ACBDs) share a conserved motif required for binding of Coenzyme A esterified fatty acids of various chain length. These proteins are present in the three kingdoms of life, and despite their predicted roles in cellular lipid metabolism, knowledge about the precise functions of many ACBD proteins remains scarce. Interestingly, several ACBD proteins are now suggested to function at organelle contact sites, and are recognized as host interaction proteins for different pathogens including viruses and bacteria. Here, we present a thorough phylogenetic analysis of the ACBD family and discuss their structure and evolution. We summarize recent findings on the various functions of animal and fungal ACBDs with particular focus on peroxisomes, the role of ACBD proteins at organelle membranes, and their increasing recognition as targets for pathogens.

Keywords: Acyl-CoA binding domain containing protein; FFAT motif; Lipid metabolism; Membrane contact sites; Pathogen host interaction; Peroxisomes

DOI: https://doi.org/10.1016/j.bbamcr.2020.118675