Drought tolerance mechanisms and aquaporin expression of wild vs. cultivated pear tree species in the field

• Published in: Environmental and experimental botany 2019-11, Vol.167, p.103832, Article 103832
• Main Authors: Paudel, Indira, Gerbi, Hadas, Zisovich, Annat, Sapir, Gal, Ben-Dor, Shifra, Brumfeld, Vlad, Klein, Tamir
• Format: Article
• Language: English
• Subjects: Aquaporin; Cultivated species; Drought; Starch; Water relations; Wild species
• ISSN: 0098-8472; 1873-7307
• DOI: 10.1016/j.envexpbot.2019.103832

•Increasing yields in cultivated fruit trees might have compromised other traits.•Drought resistance traits were compared among mature cultivated and wild pear trees.•Xylem vulnerability to embolism was lower in the wild vs. cultivated pear.•The wild pear had higher water-use efficiency than its cultivated relatives.•Among protein water channels in the xylem, two drought-induced genes were identified. Water availability is becoming a limiting factor with increasing world population that challenges global food security. Thus, we need to enhance cultivation in increasingly drier and hotter climate and prepare fruit trees for the ongoing climate change. Wild tree species might offer vital information and plant material in face of these challenges. A year-long comparative field study was conducted to investigate the mechanisms underlying drought tolerance in pear species (cultivated Pyrus communis and Pyrus pyrifolia vs. the wild Pyrus syriaca). We confirmed the hypothesis of higher drought tolerance in wild pear compared to its cultivated relative. P. syriaca xylem had fewer, narrower vessels, and lower vulnerability to embolism. It showed higher intrinsic water-sue efficiency and more robust seasonal patterns of photosynthesis, hydraulic conductivity, and PIP (plasma intrinsic protein) aquaporin expression. Across species, we identified a ubiquitous gene (PIP1:5/1:6), nine drought-inhibited genes, and two drought-induced genes (PIP1:4 and 2:6/2:7, confirming previous studies). Our study highlights the potential of using wild relatives of fruit tree species to prepare key crops to a drier and hotter future. The study of PIPs leads the way to a more focused research of the role of these cellular water channels in minimizing tree water loss under drought, while ensuring hydration of specific tissues.