Starch turnover in developing oilseed embryos

Abstract

Summary• Starch accumulates early during embryo development in Arabidopsis and oilseed rape, then disappears during oil accumulation. Little is known about the nature and importance of starch metabolism in oilseed embryos.• Histochemical and quantitative measures of starch location and content were made on developing seeds and embryos from wild-type Arabidopsis plants, and from mutants lacking enzymes of starch synthesis and degradation with established roles in leaf starch turnover. Feeding experiments with [14 C]sucrose were used to measure the rate of starch synthesis in oilseed rape embryos within intact siliques.• The patterns of starch turnover in the developing embryo are spatially and temporally complex. Accumulation is associated with zones of cell division. Study of mutant plants reveals a major role in starch turnover for glucan, water dikinase (absent from the sex1 mutant) and isoforms of beta-amylase (absent from various bam mutants). Starch is synthesized throughout the period of its accumulation and loss in embryos within intact siliques of oilseed rape.• We suggest that starch turnover is functionally linked to cell division and differentiation rather than to developmental or storage functions specific to embryos. The pathways of embryo starch metabolism are similar in several respects to those in Arabidopsis leaves.

Identification of proteins related to microspore embryogenesis responsiveness in anther cultures of winter triticale (×Triticosecale Wittm.)

“…One of the examples is beta-amylase (spot no 20) involved in the turnover of starch, an energy and carbon source necessary for cell division and differentiation (Andriotis et al 2010). In accordance with our data, upregulation of genes responsible for starch hydrolysis was detected during induction of ME in barley (Maraschin et al 2006).…”

A Cascade of Sequentially Expressed Sucrose Transporters in the Seed Coat and Endosperm Provides Nutrition for the Arabidopsis Embryo

“…Starch content was measured enzymatically following published procedures with some changes (Andriotis et al, 2010). Thirty embryos or seed coats were pooled from one plant for one analysis.…”

Environmental and varietal impact on linseed composition and on oil unidirectional expression process

“…Beyond these considerations about starch content, the very low absolute value of starch contents (below 0.3%) should be noticed. In oilseed embryos, starch is generally transiently synthetized in the early stages of seed development and then transformed in lipids and proteins (Andriotis et al, 2010;Eastmond and Rawsthorne, 2000;Troufflard, 2004;Streb and Zeeman, 2012). In flax, the maxima of starch content occurs around 20/25 days after flowering and can be up to 0.015 mg/embryo.…”