Chromosomal distribution of genes conferring tolerance to abiotic stresses versus that of genes controlling resistance to biotic stresses in plants

Authors: Wang, Richard

Submitted to: International Journal of Molecular Sciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/6/2020
Publication Date: 3/6/2020
Citation: Wang, R. 2020. Chromosomal distribution of genes conferring tolerance to abiotic stresses versus that of genes controlling resistance to biotic stresses in plants. International Journal of Molecular Sciences. 21(5). https://doi.org/10.3390/ijms21051820.
DOI: https://doi.org/10.3390/ijms21051820

Interpretive Summary: With the advent of whole-genome sequencing in many plant species, we now can physically map genes having known functions to chromosomes and then test a hypothesis on the relationship between gene function and gene location. In this Editorial, published papers in two special issues of International Journal of Molecular Sciences on genes conferring tolerance to abiotic stresses and those conferring resistance to biotic stresses were summarized and compared in term of gene locations, distal or proximal, on chromosome arms. Genes for abiotic tolerance in plants had a higher proportion of proximal distribution than those for biotic resistance. This phenomenon is explained by the fact that tolerance to abiotic stresses is controlled by complex physiological and biochemical pathways regulated by multigenic transcription factor families. In contrast, resistance to biotic stresses was mostly controlled by single genes regulating host 'resistance-pest' virulence interaction. Thus, chromosomal arrangements seem to have been optimized for maintaining plant integrity and enhancing genetic diversity to deal with threats from abiotic and biotic stresses.

Technical Abstract: Tolerance to abiotic stresses caused by environmental conditions and resistance to biotic stresses caused by diseases and insects can prevent yield loss in crops for sustaining agricultural productivity. For each crop or plant species, there are many abiotic threats, such as changes in temperature, soil salinity/alkalinity, water shortage, and soil contaminants, as well as biotic challenges from microorganisms (bacteria, viruses, and fungi), insects, and nematodes. Due to the coevolution of plants and stress-causing organisms, plants need to possess multiple resistance genes to deal with the rise of new virulence in stress-causing organisms. Plant breeders are constantly looking for new resistance genes to combat evolving organisms that pose a threat to susceptible crops. Plant geneticists have identified many resistance genes in various crops, and molecular geneticists have developed molecular markers for most of those genes. Similarly, researchers are investigating plant mechanisms and underlying genetic systems involved in plant tolerance to abiotic stresses, hoping to breed crops resilient to adverse environmental conditions. With the advent of whole-genome sequencing in many important crops, it is time to map the detailed chromosomal locations of known genes that are involved in tolerance to various abiotic stresses as well as resistance to biotic stresses in important plant species. Twenty-one and eleven papers published in the special issue "Mapping Abiotic Stress-Tolerance Genes in Plants" and "Mapping Plant Genes that Confer Resistance to Biotic Stress", respectively, of International Journal of Molecular Sciences were reviewed and genes mapped chromosomal positions were summarized. Difference in chromosomal distribution of genes for the two types of stresses was discussed as to its implications.