Towards understanding the influence of seed maturation on physiological seed quality in legumes

Author(s)

Rubiana Falopa Rossi

• Document type: Doctoral Thesis
• Press: Botucatu. 2016-10-21.
• Institution: Universidade Estadual Paulista (Unesp). Faculdade de Ciências Agronômicas. Botucatu
• Defense date: 2016-07-15
• Advisor: Edvaldo Aparecido Amaral da Silva; Olivier Leprince

Abstract

During seed maturation, germination, desiccation tolerance and longevity are acquired sequentially. Seed maturation is terminated by a desiccation phase that brings the embryo to a quiescent state. In the seed production chain, the stage of maturity at harvest is the first factor that influences seed longevity and crop establishment. After harvest, seeds are usually dried to water content compatible with long term storage and post-harvest treatments. However, there is a lack of understanding of how seed longevity is acquired during seed maturation and how premature drying impacts longevity and resumption of cellular activities during imbibition. This was addressed here by comparing transcriptome changes associated with maturation drying and imbibition of seeds of soybean and Medicago truncatula, harvested at an immature stage and mature dry stage. The immature stage corresponded to end of seed filling when longevity was not acquired while other vigor traits were acquired. Transcriptome characterization in soybean revealed that enforced drying was not similar to maturation drying in planta, which stimulated degradation of chlorophyll and synthesis of protective chaperones. Eighty-nine % of the differentially expressed genes during a 18h-imbibition period showed a similar pattern between immature and mature seeds, consistent with a comparable germination between stages. An analysis of the 147 transcripts that increased during imbibition of mature seeds but not in immature seeds suggested an activation of processes associated with shoot meristem development and DNA repair. These data were compared with imbibing immature and mature seeds of Medicago and revealed an overrepresentation of genes involved in phototropism, seed coat and innate immunity in mature seeds. This work should provide new tools to optimize harvest at maximum seed quality. (AU)

• FAPESP's process: 13/04598-8 - The influence of maturation on gene expression during seed germination and seedling establishment in soybean (Glycine max (L.) Merr.)
• Grantee: Rubiana Falopa Rossi
• Support Opportunities: Scholarships in Brazil - Doctorate