Metabolic and hormonal processes associated with the induction of secondary dormancy in Brassica napus seedsThis paper is one of a selection of papers published in a Special Issue from the National Research Council of Canada – Plant Biotechnology Institute.

Botany ◽  
2009 ◽  
Vol 87 (6) ◽  
pp. 585-596 ◽  
Author(s):  
Houman Fei ◽  
Yurdagul Ferhatoglu ◽  
Edward Tsang ◽  
Daiqing Huang ◽  
Adrian J. Cutler

Polyethylene glycol treatment induces secondary seed dormancy in Brassica napus  L. cultivar ‘AC Excel’ (ACE), but not in ‘DH12075’ (DH). Gene expression, metabolite profiles, and hormone profiles were obtained from seeds of both cultivars following polyethylene glycol 8000 treatment. ACE seeds were more transcriptionally active: 28 genes were up-regulated in both cultivars and 10 and 158 genes were specifically up-regulated in DH and ACE, respectively. Nontargeted metabolite analyses combined with gene expression analyses showed significant differences in lipid, sugar, and phenylpropanoid metabolism between the cultivars. Abscisic acid (ABA) levels were higher and many ABA-inducible genes were expressed more in ACE. An association of ABA with secondary dormancy was supported by the observation that secondary dormancy was induced by polyethylene glycol 8000 in Arabidopsis wild-type seeds, but was reduced in ABA-deficient and ABA-insensitive mutants. Therefore, secondary dormancy appears to be realized through an active ABA-related mechanism that may involve changes in primary and secondary metabolism.


Botany ◽  
2009 ◽  
Vol 87 (6) ◽  
pp. 616-625 ◽  
Author(s):  
Leonid Akhov ◽  
Paula Ashe ◽  
Yifang Tan ◽  
Raju Datla ◽  
Gopalan Selvaraj

The yellow seed characteristic in Brassica napus  L. is desirable because of its association with higher oil content and better quality of oil-extracted meal. YN01-429 is a yellow-seeded canola-quality germplasm developed in Canada arising from several years of research. Seed-coat pigmentation is due to oxidized proanthocyanidins (PA; condensed tannins) derived from phenylpropanoids and malonyl CoA. We found PA accumulation to be most robust in young seed coats (20 d post anthesis; dpa) of a related black-seeded line N89-53 and only very little PA in YN01-429, which also contained much less extractable phenolics. The flavonol content, however, did not show as great a difference between these two lines. Furthermore, sinapine, a product of the general phenylpropanoid metabolism, was present at comparable levels in the embryos of both lines. Dihydroflavonol reductase (DFR) activity that commits phenolics to PA synthesis was lower in YN01-429 seed coats. The results of Southern blot and in silico analyses were indicative of two copies of the DFR gene in B. napus. Both copies were functional in YN01-429, ruling out homeoallelic repression or silencing, but together they showed very low expression levels (17-fold fewer transcripts) relative to DFR activity in N89-53 seed coats. These results collectively suggest that YN01-429 differs in regulatory circuits that impact the PA synthesis branch much more than the flavonol synthesis branch in the seed coats and such circuits do not impinge upon general phenylpropanoid metabolism in the embryos.



Botany ◽  
2009 ◽  
Vol 87 (6) ◽  
pp. 597-603 ◽  
Author(s):  
Cheryl Bock ◽  
Heather Ray ◽  
Fawzy Georges

The utility of defatted seed meal from many crops such as canola ( Brassica napus  L.) is limited by the presence of antinutritional factors, including sucrose galactosides, raffinose, and stachyose. Anaerobic breakdown of these sugars in the digestive tract of livestock is a major source of production of farm gases. In this report, the gene encoding galactinol synthase was isolated from B. napus and reintroduced into the same species in an antisense orientation to limit the production of galactinol, an important intermediate in the biosynthesis of raffinose and stachyose. This approach substantially reduced the accumulation of galactinol and stachyose in mature transgenic canola seed. Substantial changes in the mRNA levels of galactinol synthase and several sugar-related genes were also observed.



2021 ◽  
Vol 22 (3) ◽  
pp. 1033
Author(s):  
Abirami Rajavel ◽  
Selina Klees ◽  
Johanna-Sophie Schlüter ◽  
Hendrik Bertram ◽  
Kun Lu ◽  
...  

Transcription factors (TFs) and their complex interplay are essential for directing specific genetic programs, such as responses to environmental stresses, tissue development, or cell differentiation by regulating gene expression. Knowledge regarding TF–TF cooperations could be promising in gaining insight into the developmental switches between the cultivars of Brassica napus L., namely Zhongshuang11 (ZS11), a double-low accession with high-oil- content, and Zhongyou821 (ZY821), a double-high accession with low-oil-content. In this regard, we analysed a time series RNA-seq data set of seed tissue from both of the cultivars by mainly focusing on the monotonically expressed genes (MEGs). The consideration of the MEGs enables the capturing of multi-stage progression processes that are orchestrated by the cooperative TFs and, thus, facilitates the understanding of the molecular mechanisms determining seed oil content. Our findings show that TF families, such as NAC, MYB, DOF, GATA, and HD-ZIP are highly involved in the seed developmental process. Particularly, their preferential partner choices as well as changes in their gene expression profiles seem to be strongly associated with the differentiation of the oil content between the two cultivars. These findings are essential in enhancing our understanding of the genetic programs in both cultivars and developing novel hypotheses for further experimental studies.



2019 ◽  
Vol 60 (12) ◽  
pp. 2812-2825 ◽  
Author(s):  
Pan Liao ◽  
Helen K Woodfield ◽  
John L Harwood ◽  
Mee-Len Chye ◽  
Simon Scofield

Abstract Production of vegetable oils is a vital agricultural resource and oilseed rape (Brassica napus) is the third most important oil crop globally. Although the regulation of lipid biosynthesis in oilseeds is still not fully defined, the acyl-CoA-binding proteins (ACBPs) have been reported to be involved in such metabolism, including oil accumulation, in several plant species. In this study, progressive changes in gene expression in embryos and seed coats at different stages of seed development were comprehensively investigated by transcriptomic analyses in B. napus, revealing dynamic changes in the expression of genes involved in lipid biosynthesis. We show that genes encoding BnACBP proteins show distinct changes in expression at different developmental stages of seed development and show markedly different expression between embryos and seed coats. Both isoforms of the ankyrin-repeat BnACBP2 increased during the oil accumulation period of embryo development. By contrast, the expression of the three most abundant isoforms of the small molecular mass BnACBP6 in embryos showed progressive reduction, despite having the highest overall expression level. In seed coats, BnACBP3, BnACBP4 and BnACBP5 expression remained constant during development, whereas the two major isoforms of BnACBP6 increased, contrasting with the data from embryos. We conclude that genes related to fatty acid and triacylglycerol biosynthesis showing dynamic expression changes may regulate the lipid distribution in embryos and seed coats of B. napus and that BnACBP2 and BnACBP6 are potentially important for oil accumulation.



2000 ◽  
Vol 156 (2) ◽  
pp. 175-183 ◽  
Author(s):  
Lilian Nehlin ◽  
Christian Möllers ◽  
Per Bergman ◽  
Kristina Glimelius


2009 ◽  
Vol 89 (4) ◽  
pp. 613-619 ◽  
Author(s):  
S Gruber ◽  
K Emrich ◽  
W Claupein

Secondary dormancy is the major reason for seed persistence of canola (Brassica napus L.) in the soil. Volunteers emerging from the soil seed bank can lead to unwanted gene dispersal. More than 40 B. napus canola cultivars were tested for secondary dormancy under laboratory conditions. All cultivars were classified into groups of low, medium, and high dormancy by performing a cluster analysis. The results suggest that secondary dormancy is a cultivar-specific trait. Additionally, inter-year variation in dormancy indicates that it seems to be influenced by a set of environmental factors. Among years, classification of cultivars based on relative rank was more robust than classification based on absolute dormancy values. The classification of cultivars by their dormancy level would allow farmers to select and grow low-dormancy cultivars. Knowledge about the relative secondary dormancy of the currently grown cultivars could help growers and breeders lower canola seed bank persistence. Key words: Brassica napus, cluster analysis, genotype, secondary dormancy, soil seed bank



2016 ◽  
Vol 62 (3) ◽  
pp. 254-262 ◽  
Author(s):  
D. Liu ◽  
L. Y. Hu ◽  
B. Ali ◽  
A. G. Yang ◽  
G. L. Wan ◽  
...  


Sign in / Sign up

Export Citation Format

Share Document