Effects of altered expression of LEAFY COTYLEDON1 and FUSCA3 on microspore-derived embryogenesis of Brassica napus L.

Abstract

Brassica napus (Bn) microspore-derived embryogenesis has become a model system to study basic aspects of plant development. Recognized transcription factors governing embryogenesis include: FUSCA3 (FUS3), a member of the plant-specific B3-domain family, and LEAFY COTYLEDON1 (LEC1), a member of the HAP3 subunit of the CCAAT binding factor family. The effects of altered expression of both genes were investigated during microspore-derived embryogenesis in established B. napus lines over-expressing or down-regulating BnLEC1, as well as in tilling lines where BnFUS3 was mutated. While over-expression of BnLEC1 decreases the yield of microspore-derived embryos (MDEs) without affecting their ability to regenerate plants, suppression of BnLEC1 or BnFUS3 reduced both embryo number and regeneration frequency. Embryos produced by these lines showed structural abnormalities accompanied by alterations in the expression of several embryogenesis-marker genes. Oil accumulation was also altered in the transgenic MDEs. Total oil content was increased in MDEs over-expressing BnLEC1 and decreased in those suppressing BnLEC1 or BnFUS3. Mutation of BnFUS3 also resulted in a small but significant increase in linoleic (C18:2) acid. Together this study demonstrates the crucial role of BnLEC1 and BnFUS3 during in vitro embryogenesis.

Overexpression of the AtWUSCHEL gene promotes somatic embryogenesis and lateral branch formation in birch (Betula platyphylla Suk.)

“…The difference in induced expression of AtLEC1 and AtLEC2 promoted somatic embryogenesis in transgenic tobacco plants (Guo, et al 2013). The expression changes of LEC1 and FUS3 affected microspore embryogenesis in Brassica napus (Elahi, et al 2016). LEC2 is an important WUS response factor.…”

Genetic Loci Governing Androgenic Capacity in Perennial Ryegrass (Lolium perenne L.)

“…In fact, LEC1 , LEC2 and FUS3 are overexpressed in clf swn double mutants of Arabidopsis ( Makarevich et al 2006 ). Indeed, LEC1 (over-)expression was shown to negatively affect ME in both rapeseed and rye ( Gruszczyńska and Rakoczy-Trojanowska 2011 ; Elahi et al 2016 ). Interestingly, a homolog of the MADS box gene AGL26 , was annotated along with FIE on scaffold 4385.…”

“…Overexpression of the APETALA 2 ( AP2 ) transcription factor BABYBOOM ( BBM ), WUSCHEL ( WUS ) and AGAMOUS -like ( AGL ) genes, led to the production of ectopic somatic embryos in Arabidopsis , rapeseed and a number of monocot species and improved in vitro regeneration frequencies ( Boutilier 2002 ; Muñoz-Amatriaín et al 2009b ; Lowe et al 2016 ). Other examples of genes that may be associated with ME are the arabinogalactan-related EARLY CULTURE ABUNDANT 1 ( ECA1 ) ( Vrinten et al 1999 ), Polycomb Group (PcG) proteins including FERTILIZATION INDEPENDENT ENDOSPERM ( FIE ) ( Hand et al 2016 ), BURP-domain proteins like BnBNM2 ( Boutilier 2002 ; Tsuwamoto et al 2007 ; Joosen et al 2007 ; Malik et al 2007 ) and the LEAFY COTYLEDON ( LEC ) family of transcription factors ( Gruszczyńska and Rakoczy-Trojanowska 2011 ; Soriano et al 2013 ; Elahi et al 2016 ). Similar to linkage mapping studies, the use of different species, treatments and gene expression platforms as well as the complexity of the system under study, prohibit conclusive identification of the genes of greatest importance to successful androgenesis ( Soriano et al 2013 ).…”

Plant cell totipotency: Insights into cellular reprogramming

“…Recent studies on the roles of major transcription factors and epigenetic factors (Table 1) and their genetic and molecular interactions in 2,4-D-mediated somatic embryogenesis have uncovered a complex interacting network that regulates hormonal pathways, particularly the auxin pathway ( Figure 2). When overexpressed, the transcription factors LEC1, LEC2, and BBM specify totipotent cell identity Lotan et al, 1998 Brassica napus Elahi et al, 2016 Capsicum annum Irikova et al, 2012 Coffea canephora Nic-Can et al, 2013…”