Ribonucleases are naturally occurring enzymes, which degrade Ribonucleic acid, or RNA, and serve as vital components of defense systems against viral, bacterial and parasitic infections.
Notably, genes with extreme fold differences between the two alleles in the heterozygote either confer tolerance or are important components of defense systems under stress conditions.
HSPs are critical components of defense mechanism against injury associated with adverse stresses [24].
Most of them encode the components of defense signal transduction pathways and provide nonspecific resistance to a broad spectrum of pathogens [2], [3].
Collectively, the literature on population genetic analysis of evolutionary patterns at host resistance genes indicates that the dominant form of selection acting on defense genes differs among different components of defense mechanisms [7].
A predominant theme that is emerging is that of ubiquitination as a means of targeting components of defense signaling pathways for degradation to curtail the plant immune response [12], [13].
The recognition of fungal cell wall compounds through PRRs is the beginning of the immune response, and the first components of defense against Aspergillus spp. in the alveoli are the alveolar macrophages, which phagocyte dormant or swollen spores, killing only swollen spores, especially due to the capability of lung resident macrophages to produce ROS [ 131].
Based on the expression of osmotins and aquaporins and other genes involved in galactinol and trehalose biosynthesis, maintenance of root and leaf water balance and cellular osmotic adjustment (GO 0005992, GO 0009719; see Additional file 5) are important components of defense mechanism [ 98- 100].
However, the disease resistance genes annotated in the report were predicted from their DNA sequence similarity with sequences encoding NBS and/or LRR domains, therefore there was no direct evidence indicating they truly function as R genes or components of defense signaling.
It is good practice to apply a defense-in-depth strategy, using multiple security techniques to mitigate the risk of one component of the defense being compromised or circumvented.
