Stress-Induced Proteins in Recalcitrant Seeds During Deep Dormancy and Early Germination

Abstract

The role and functions of dehydrins and heat shock proteins in seeds especially in desiccation-sensitive recalcitrant seeds are discussed.During the periods of dehydration, a wide variety of plants can express dehydration proteins dehydrins , which are also members of the plant late embryogenesis abundant LE" protein family. Dehydrins have been most extensively studied in relation to drought and cold stresses. Dehydrins are synthesized in orthodox seeds, and their development at the final stage is associated with genetically determined seeds drying. Dehydrins amount can reach % of total cell proteins. "t the same time, dehydrins are found in desiccation-sensitive recalcitrant seeds. The following are the functions of dehydrins with experimental evidence binding to water and ions, binding to phospholipids, radical scavenging, phosphorylation, binding to calcium, protection of enzymes, binding to cytoskeletons, and binding to nucleic acids.It seems evident that, in the embryo cells, heat shock induced changes in gene expression and HSP synthesis but did not result in translational discrimination of mRN"s for nonheat shock proteins. Such specific feature has been observed earlier for orthodox seeds during their development and early stages of germination. It is suggested that such response to HS is characteristic just of embryo tissues it could be considered an additional molecular mechanism improving embryo tolerance to unfavorable environmental conditions.

Proteomic Analysis of Pigeonpea (Cajanus cajan) Seeds Reveals the Accumulation of Numerous Stress-Related Proteins

“…This enables the seeds to maintain viability for long periods. On the basis of physiological function, these proteins can be grouped into molecular chaperones, antioxidative proteins, and late embryogenesis abundant (LEA) proteins . Our proteomic analysis revealed several proteins that can be classified as stress-related proteins (Table ).…”

Synthetic seeds and their role in agriculture: status and progress in sub-Saharan Africa

“…Additionally, when the developmental programme of the individual mature ovules is switched over from embryogenesis to germination, various cell activities change on the level of gene expression, especially when seed embryos are subjected to unfavourable environmental stresses. The germinating seed embryos induce the synthesis of anti-stress proteins to protect themselves and continue with seedling development (32). Gene expression is responsible for the accumulation of dehydrin proteins as a result of drought, chilling, salinity and heat shock proteins as well as chaperones.…”

“…Studies emphasised that, the necessary investments in agriculture, particularly those that would improve the low crop productivity as demonstrated in Fig. 1 B, requires seeds that immediately respond to dormancy-breaking stimuli and germination cues under appropriate conditions (28,(30)(31)(32). Even though seed research has evolved, and productivity/ improvement outcomes greatly varies across countries (Fig.…”

“…Generally, seeds are classified into recalcitrant and orthodox seed types based on their ability to germinate following rehydration under optimum growth conditions (37). For orthodox seeds, known as desiccation tolerant, rapid changes in moisture content and metabolism contribute to high seed viability, as well as the high rate of germination upon subsequent receiving of adequate moisture (32,37). Unlike orthodox seeds, legume seed desiccation is directly associated with seed deterioration on both quality and germinability (14,18,30).…”

Responses to chilling and cryopreservation of recalcitrant seeds of Ekebergia capensis from different provenances

“…Dehydrins are a specific class of LEA proteins, and have been suggested to play a fundamental role in the response of plant tissues to dehydration (Close, 1996; and drought tolerance in orthodox seeds (Azarkovich, 2015). The multiple targets of dehydrins suggest that the direct consequences of dehydrin activity are biochemically diverse (Close, 1996).…”