Activating stress memory: eustressors as potential tools for plant breeding.

Plants are continuously exposed to stress conditions, such that they have developed sophisticated and elegant survival strategies, which are reflected in their phenotypic plasticity, priming capacity, and memory acquisition. Epigenetic mechanisms play a critical role in modulating gene expression and stress responses, allowing malleability, reversibility, stability, and heritability of favourable phenotypes to enhance plant performance. Considering the urgency to improve our agricultural system because of going impacting climate change, potential and sustainable strategies rely on the controlled use of eustressors, enhancing desired characteristics and yield and shaping stress tolerance in crops. However, for plant breeding purposes is necessary to focus on the use of eustressors capable of establishing stable epigenetic marks to generate a transgenerational memory to stimulate a priming state in plants to face the changing environment.

Differential expression of Phaseolus vulgaris genes induced during the interaction with Rhizoctonia solani.

Common bean (Phaseolus vulgaris L.) is the most important grain legume for direct human consumption; however, bean production is affected by several diseases such as Rhizoctonia root rot. Few bean cultivars have been identified that effectively resist the attack of this fungus. Herein, we used the P. vulgaris Pv-2094 landrace, which is less susceptible to Rhizoctonia root rot, for the construction of a suppressive subtractive hybridization cDNA library in order to isolate plant defense-related genes. Total RNAs obtained after 8 and 16 h from inoculated and non-inoculated roots with R. solani Kühn, were used as the source of the "tester" and the "driver" samples, respectively. A total of 136 unigenes were obtained and classified into 12 functional categories. Six unigenes were selected to analyze for differential expression by qRT-PCR, including a receptor-like kinase (PvRK20-1), an acid phosphatase associated to defense (PA), a pathogenesis related protein (PR1), an ethylene responsive factor (ERF), a polygalacturonase inhibitor protein (PGIP), and an alpha-dioxygenase (α-DOX). These genes were found to be differentially expressed in a time-dependent manner in bean roots during the interaction with R. solani. Data generated from this study will contribute to the understanding of the molecular mechanisms associated with plant defense against root rot in common bean.