ABSTRACT
KEY MESSAGE: Transcriptome analysis of barley embryogenic callus from isolated microspore culture under salt stress uncovered a role of translation inhibition and selective activation of stress-specific proteins in cellular defense. Soil salinity is one of the major abiotic stresses which constrains the plant growth and reduces the productivity of field crops. In this study, it was observed that the salt stress in barley isolated microspore culture impacted not only on the quantity of embryogenic callus but also on the quality for later differentiation. The barley microspore-derived embryogenic callus, a transient intermediate form linked cells and plants, was employed for a global transcriptome analysis by RNA sequencing to provide new insights into the cellular adaptation or acclimation to stress. A total of 596 differentially expressed genes (DEGs) were identified, in which 123 DEGs were up-regulated and 473 DEGs were down-regulated in the embryogenic callus produced from microspore culture under salt stress as compared to the control conditions. KEGG pathway analysis identified 'translation' (27 DEGs; 12.56 %) as the largest group and followed by 'folding, sorting and degradation' (25 DEGs; 11.63 %) in 215 mapped metabolic pathways. The results of RNA-Seq data and quantitative real-time polymerase chain reaction validation showed that the genes related to translation regulation (such as eIF1A, RPLP0, RPLP2, VARS) were down-regulated to control general protein synthesis, and the genes related to endoplasmic reticulum stress response (such as small heat shock protein genes) were selectively up-regulated against protein denaturing during microspore embryogenesis under continuous salt stress. These transcriptional remodeling might affect the essential protein synthesis for the cell development to fulfill totipotency under salt stress.
Subject(s)
Gene Expression Profiling , Hordeum/embryology , Hordeum/genetics , Pollen/genetics , Pollen/physiology , Protein Biosynthesis/genetics , Sodium Chloride/pharmacology , Stress, Physiological/genetics , Gene Expression Regulation, Plant , Hordeum/drug effects , Hordeum/physiology , Pollen/drug effects , Protein Biosynthesis/drug effects , Real-Time Polymerase Chain Reaction , Seeds/drug effects , Seeds/embryology , Seeds/genetics , Seeds/physiology , Sequence Analysis, RNA , Signal Transduction/drug effects , Signal Transduction/genetics , Stress, Physiological/drug effectsABSTRACT
Using maize anthers of 2 cultivars as experimental materials, the effects of mannitol, colchcine and proline concentration in pretreatment solution and pretreating temperature on the survival percentage of isolated microspore were investigated. The survival percentage of isolated microspores were able to be respectively and obviously improved by pretreating anthers with mannitol from low to high concentration (0.35 mol/L, 24h --> 0.40 mol/L, 24h --> 0.45 mol/L, 24h), or with colchicine 200 mg/L or with proline 200 mg/L and pretreating at 15 degrees C for 48h. The probable mechanism of pretreatments was discussed.
