Modulation of autophagy and protease activities by small bioactive compounds to reduce cell death and improve stress-induced microspore embryogenesis initiation in rapeseed and barley

ABSTRACTMicrospore embryogenesis is a powerful biotechnological tool that is very useful in crop breeding for the rapid production of haploid and double-haploid embryos and plants. In this in vitro system, the haploid microspore is reprogrammed by the application of specific stress treatments. A high level of cell death after the stress is a major factor that greatly reduces embryogenesis yield at its initial stages. Autophagy is a degradation pathway that is present in all eukaryotes and plays key roles in a range of processes, including stress responses. Many proteases participate in autophagy and cell death; among them, cathepsins are the most abundant enzymes with a role in plant senescence and programmed cell death (PCD). Moreover, although plant genomes do not contain homologues of caspases, caspase 3-like activity (main executioner protease of animal cell death) has been detected in many plant PCD processes. Recent studies by our group in barley microspore cultures reported that the stress treatmen...