Androgenic switch in barley microspores

Abstract

Barley androgenesis represents an attractive system to study stress-induced cell differentiation and is a valuable tool for efficient plant breeding. The switch from the pollen developmental pathway towards an androgenic route involves several well-described morphological changes. However, little is known about the pathways leading to embryo formation and about the transcriptome of androgenic microspores. The research described in this thesis aimed to identify new "bio-markers" for barley androgenesis induction and embryo development. The concept of a "bio-marker" is not a single gene, protein, metabolite or phenotype. It refers to the concept of understanding biological events, such as gene expression profiles or morphological changes at certain biological states. The work presented in this thesis has provided a substantial contribution towards understanding the mechanisms of androgenesis induction.The use of a cell tracking system in combination with biochemical markers has been crucial in pointing out that the morphology of embryogenic microspores, and in identifying programmed cell death as an integral part of the developmental pathway of androgenic embryos. In addition, the markers identified in this thesis by cDNA array and 14-3-3 expression analyses represent useful tools for further analysis of stress-induced androgenesis and pattern formation in androgenic embryos. Understanding the role of these markers, as well as the role of programmed cell death during exine wall rupture and subsequent pattern formation represents a future challenge for the improvement of quality and yield of androgenic embryos.UBL - phd migration 201