Exogenously applied Casuarina equisetifolia leaf extracts act as an osmoprotectant on proline accumulation under drought stress in local rice from Indonesia

The effects of exogenously supplied osmoprotectants in crops have not yet been extensively studied. In this study, an osmoprotectant containing a high concentration of proline (2.5 g mol-1 FW) was obtained from a Casuarina equisetifolia leaf extract. The effect of the extract was evaluated in local Indonesian rice cultivars Boawae Seratus Malam (BSM), Gogo Jak (GJ), Situ Bagendit (SB) (drought-tolerant), Kisol Manggarai (KM) and Ciherang (drought-susceptible) cultivars under drought at the morphological, physiological, and genetic levels. Under drought, the KM showed an increased level of OsWRKY, OsNAC, OsDREB1A, and OsDREB2A expression after application of the osmoprotectant, leading to the activation of proline synthesis genes including OsP5CS1, OsP5CR, and OsProDH, while the tolerant cultivars (BSM, GJ, and SB) showed no difference. The content of chlorophyll, carotenoids, anthocyanins, ascorbate peroxidase, catalase, and superoxide dismutase activities also increased in GJ and KM, during drought stress and applied osmoprotectants, but remained low in the BSM. We conclude that the foliar application of osmoprotectants derived from C.equisetifolia caused an accumulation of proline in susceptible plants. The existence of these extracts stabilizes leaf cells and supports photosynthetic compartments and carbon assimilation in plants, leading to growth.

Protein Profile of Tissue Culture of TRI2025 Tea Clone

Tea is well known as favourite healthy drink for almost all people over the world. Tea propagation using conventional and modern ways are now developing rapidly. However, information regarding the protein profile of tissue culture of tea plant has not been revealed yet. This study aimed to determine the difference of protein profile of tea’s tissue culture using SDS-PAGE. This study was conducted using embryonic axes of TRI2025 tea clone cultured on MS media supplemented with 2,4-D for inducing somatic embryogenesis and globular-like structure (GLS) regeneration, and MS media supplemented with BAP for inducing shoot via organogenesis. The results revealed that proteins in the size of 37.69; 54.89; 60.77; 71.35; 87.34; and 92.99 KDa might be involved at somatic embryogenesis, and about 38.69 KDa, 69.27 KDa, and 55.76 KDa respectively for GLS, initiation of shoot, and initiation of GLS derived leaf. Predicted key protein for leaf initiation both directly or through GLS was about 31-33 KDa, while for callusing were about 27.56 and 52.73 KDa, and constitutive protein was about 22.75 KDa. This study provides the first report of protein profile of tea’s tissue culture. The information obtained can be beneficial as a marker for explant for somatic embryogenesis, GLS, or organogenesis pathway and as a scientific information for further biotechnology development.