Genetic engineering for stress tolerance in the Triticeae

Abstract

SynopsisGenetic variation within a crop species is often limited and restricts improvement by conventional breeding methods. This is particularly true for environmental stresses, both biotic and abiotic. Wild relatives of crop plants, however, provide a rich source of novel variation which can be introduced into the crop. Many alien genes for biotic stress resistance have already been introduced into crops; in contrast, the genetic control of abiotic stress tolerance is poorly understood. Genetic engineering of abiotic stress tolerance in the Triticeae is the main subject discussed here with particular reference to salt tolerance in wheat and barley. Methods of alien gene transfer, including locating tolerance genes and restructuring chromosomes, are described. One of the major limitations in transferring genes for stress tolerance is the lack of good tests for resistance or tolerance which is largely due to the fact the physiological mechanisms involved are not fully understood. Genetic markers provide a new opportunity of detecting chromosome segments carrying desired genes easily and efficiently, and these will become increasingly important as the genetic maps of crop species are expanded. Although many stress genes have been located to specific chromosomes, and some have been mapped intra-chromosomally and their dominance relations determined, there is a great lack of knowledge of the control of these genes at the molecular level. Molecular studies of this type are difficult, but it is anticipated that the limitations will be overcome in the near future.

Genome-wide Identification and Evolutionary Analysis of NBS-LRR Genes From Secale cereale

“…These crops are cultivated worldwide and are frequently challenged by pathogens and pests during their growth. Although resistance breeding has improved the performance of Triticeae crops ( Forster, 1992 ; Delventhal et al, 2017 ), only a few functional R genes have been cloned from these crops ( Kourelis and van der Hoorn, 2018 ). The recently released reference genome and pan-genome of wheat and barley have accelerated the identification of functional R genes more efficiently in these species ( Jayakodi et al, 2020 ; Walkowiak et al, 2020 ).…”