bims-plasge 2022-08-28 papers

Int J Mol Sci. 2022 Aug 16. pii: 9198. [Epub ahead of print]23(16):

Comparison of Mitochondrial Genomes between a Cytoplasmic Male-Sterile Line and Its Restorer Line for Identifying Candidate CMS Genes in Gossypium hirsutum.

Lisha Xuan, Guoan Qi, Xiaoran Li, Sunyi Yan, Yiwen Cao, Chujun Huang, Lu He, Tianzhen Zhang, Haihong Shang, Yan Hu.

As the core of heterosis utilization, cytoplasmic male sterility (CMS) has been widely used in hybrid seed production. Previous studies have shown that CMS is always closely related to the altered programming of mitochondrial genes. To explore candidate CMS genes in cotton (Gossypium hirsutum), sequencing and de novo assembly were performed on the mitochondrial genome of the G. hirsutum CMS line SI3A, with G. harknessii CMS-D2 cytoplasm, and the corresponding G. hirsutum restorer line 0-613-2R. Remarkable variations in genome structure and gene transcripts were detected. The mitochondrial genome of SI3A has three circle molecules, including one main circle and two sub-circles, while 0-613-2R only has one. RNA-seq and RT-qPCR analysis proved that orf606a and orf109a, which have a chimeric structure and transmembrane domain, were highly expressed in abortive anthers of SI3A. In addition, comparative analysis of RNA-seq and full-length transcripts revealed the complex I gene nad4 to be expressed at a lower level in SI3A than in its restorer and that it featured an intron retention splicing pattern. These two novel chimeric ORFs and nad4 are potential candidates that confer CMS character in SI3A. This study provides new insight into the molecular basis of the nuclear-cytoplasmic interaction mechanism, and that putative CMS genes might be important sources for future precise design cross-breeding of cotton.

Keywords: CMS-associated gene; cotton (Gossypium hirsutum); cytoplasmic male sterility (CMS); full-length transcriptome; mitochondrial genome

DOI: https://doi.org/10.3390/ijms23169198

Cells. 2022 Aug 16. pii: 2548. [Epub ahead of print]11(16):

A Genomic BSAseq Approach for the Characterization of QTLs Underlying Resistance to Fusarium oxysporum in Eggplant.

Maria Rosaria Tassone, Paolo Bagnaresi, Francesca Desiderio, Laura Bassolino, Lorenzo Barchi, Francesco Elia Florio, Francesco Sunseri, Tiziana Maria Sirangelo, Giuseppe Leonardo Rotino, Laura Toppino.

Eggplant (Solanum melongena L.), similar to many other crops, suffers from soil-borne diseases, including Fusarium oxysporum f. sp. melongenae (Fom), causing wilting and heavy yield loss. To date, the genetic factors underlying plant responses to Fom are not well known. We previously developed a Recombinant Inbred Lines (RILs) population using as a female parent the fully resistant line '305E40' and as a male parent the partially resistant line '67/3'. The fully resistant trait to Fom was introgressed from the allied species S. aethiopicum. In this work, the RIL population was assessed for the responses to Fom and by using a genomic mapping approach, two major QTLs on chromosomes CH02 and CH11 were identified, associated with the full and partial resistance trait to Fom, respectively. A targeted BSAseq procedure in which Illumina reads bulks of RILs grouped according to their resistance score was aligned to the appropriate reference genomes highlighted differentially enriched regions between resistant/susceptible progeny in the genomic regions underlying both QTLs. The characterization of such regions allowed us to identify the most reliable candidate genes for the two resistance traits. With the aim of revealing exclusive species-specific contigs and scaffolds inherited from the allied species and thus associated with the full resistance trait, a draft de-novo assembly of available Illumina sequences of the '305E40' parent was developed to better resolve the non-recombining genomic region on its CH02 carrying the introgressed Fom resistance locus from S. aethiopicum.

Keywords: Solanum melongena; biotic stress; molecular mapping; recombinant inbred lines (RILs); resistance genes; soil-borne fungal pathogens

DOI: https://doi.org/10.3390/cells11162548

New Phytol. 2022 Aug 23.

Developmental evidence for parental conflict in driving Mimulus species barriers.

Gabrielle D Sandstedt, Andrea L Sweigart.

The endosperm, a tissue that nourishes the embryo in the seeds of flowering plants, is often disrupted in inviable hybrid seeds between closely related species. A key question is whether parental conflict is a major driver of this common form of reproductive isolation. Here, we performed reciprocal crosses between pairs of three monkeyflower species (Mimulus caespitosa, M. tilingii, and M. guttatus). The severity of hybrid seed inviability varies among these crosses, which we inferred to be due to species divergence in effective ploidy. By performing a detailed time series of seed development, we discovered parent-of-origin phenotypes that provide strong evidence for parental conflict in shaping endosperm evolution. We found that the chalazal haustorium, a tissue within the endosperm that occurs at the maternal-filial boundary, shows pronounced differences between reciprocal hybrid seeds formed from Mimulus species that differ in effective ploidy. These parent-of-origin effects suggest that the chalazal haustorium might act as a mediator of parental conflict, potentially by controlling sucrose movement from the maternal parent into the endosperm. Our study suggests that parental conflict in the endosperm may function as a driver of speciation by targeting regions and developmental stages critical for resource allocation and thus proper seed development.

Keywords: Mimulus; chalazal; endosperm; hybrid seed inviability; parental conflict; speciation

DOI: https://doi.org/10.1111/nph.18438