Programmed Proteome Response for Drought Avoidance/Tolerance in the Root of a C3 Xerophyte (Wild Watermelon) Under Water Deficits

Abstract

Water availability is a critical determinant for the growth and ecological distribution of terrestrial plants. Although some xerophytes are unique regarding their highly developed root architecture and the successful adaptation to arid environments, virtually nothing is known about the molecular mechanisms underlying this adaptation. Here, we report physiological and molecular responses of wild watermelon (Citrullus lanatus sp.), which exhibits extraordinarily high drought resistance. At the early stage of drought stress, root development of wild watermelon was significantly enhanced compared with that of the irrigated plants, indicating the activation of a drought avoidance mechanism for absorbing water from deep soil layers. Consistent with this observation, comparative proteome analysis revealed that many proteins induced in the early stage of drought stress are involved in root morphogenesis and carbon/nitrogen metabolism, which may contribute to the drought avoidance via the enhancement of root growth. On the other hand, lignin synthesis-related proteins and molecular chaperones, which may function in the enhancement of physical desiccation tolerance and maintenance of protein integrity, respectively, were induced mostly at the later stage of drought stress. Our findings suggest that this xerophyte switches survival strategies from drought avoidance to drought tolerance during the progression of drought stress, by regulating its root proteome in a temporally programmed manner. This study provides new insights into the complex molecular networks within plant roots involved in the adaptation to adverse environments.

Drought-induced changes in the actin cytoskeleton of barley (Hordeum vulgare L.) leaves

“…ACT11 gene was reported also before as being unstable under drought treatment ). This outcome is in agreement with previously published results, showing the involvement of actin in the regulation of drought-response in watermelon roots (Yoshimura et al 2008). The drought-induced changes in the reorganization of AFs within epidermis and mesophyll is accompanied by the activation of genes involved in the perception of drought stress and in the transmission of the stress signal (Shinozaki and Yamaguchi-Shinozaki 2007).…”

Proteomics Analysis of Drought Stress-Responsive Proteins in Hippophae rhamnoides L.

“…In E. coli, HslU can combine with HslV to form a protease to remove abnormal proteins (Wu et al 1999) and also can function as chaperone to prevent the aggregation of denatured protein (Seong et al 2000). Drought can increase the abundance of large heat shock protein (Yoshimura et al 2008). However, supporting our research, there was also a report which suggested that drought decreased the abundance of large heat shock protein (Rizhsky et al 2002).…”

Potencial hídrico do substrato e teor de água das sementes na germinação do crambe

“…Muitas proteínas que são induzidas nos estágios iniciais do estresse hídrico são também envolvidas na morfogênese da raiz e no metabolismo de carbono/nitrogênio, as quais podem contribuir para a anulação do estresse por meio do aumento do crescimento radicular (Yoshimura et al, 2008). No caso do crambe, a literatura relata que trata-se de uma planta adaptada a condições inóspitas (Pitol, 2007) e tal rusticidade pode favorecer a tolerância das sementes sob diversas condições.…”