MYB43 in Oilseed Rape (Brassica napus) Positively Regulates Vascular Lignification, Plant Morphology and Yield Potential but Negatively Affects Resistance to Sclerotinia sclerotiorum

Arabidopsis thaliana MYB43 (AtMYB43) is suggested to be involved in cell wall lignification. PtrMYB152, the Populus orthologue of AtMYB43, is a transcriptional activator of lignin biosynthesis and vessel wall deposition. In this research, MYB43 genes from Brassica napus (rapeseed) and its parental species B. rapa and B. oleracea were molecularly characterized, which were dominantly expressed in stem and other vascular organs and showed responsiveness to Sclerotinia sclerotiorum infection. The BnMYB43 family was silenced by RNAi, and the transgenic rapeseed lines showed retardation in growth and development with smaller organs, reduced lodging resistance, fewer silique number and lower yield potential. The thickness of the xylem layer decreased by 28%; the numbers of sclerenchymatous cells, vessels, interfascicular fibers, sieve tubes and pith cells in the whole cross section of the stem decreased by 28%, 59%, 48%, 34% and 21% in these lines, respectively. The contents of cellulose and lignin decreased by 17.49% and 16.21% respectively, while the pectin content increased by 71.92% in stems of RNAi lines. When inoculated with S. sclerotiorum, the lesion length was drastically decreased by 52.10% in the stems of transgenic plants compared with WT, implying great increase in disease resistance. Correspondingly, changes in the gene expression patterns of lignin biosynthesis, cellulose biosynthesis, pectin biosynthesis, cell cycle, SA- and JA-signals, and defensive pathways were in accordance with above phenotypic modifications. These results show that BnMYB43, being a growth-defense trade-off participant, positively regulates vascular lignification, plant morphology and yield potential, but negatively affects resistance to S. sclerotiorum. Moreover, this lignification activator influences cell biogenesis of both lignified and non-lignified tissues of the whole vascular organ.

Polymorphism of microsatellite loci in feral populations and commercial varieties of oilseed rape (Brassica napus L.)

Aim. The aim of the work was to compare the polymorphism of commercial varieties and populations of B. napus growing outside cultivation to assess the genetic diversity of feral rapeseed populations in Belarus. Methods. The study assessed genetic diversity according to the data of 7 microsatellite loci genotyping. Results. The results indicate a greater genetic diversity in feral oilseed rape populations. An analysis of the structure of the genotypes distribution in the STRUCTURE software showed the division into three clusters – commertial varieties, feral populations and samples of B. rapa. Conclusions. The established genetic divergence between feral populations and commercial varieties indicates that feral oilseed rape is able to maintain persistent populations in Belarus. In practice, this should be taken into account when assessing the environmental risk when transgenic rape is released into the environment. And in the cultivation of transgenic rapeseed, special attention should be paid to measures to prevent the occurrence of its free-growing populations. Keywords: oilseed rape, feral populations, microsatellite loci, genetic diversity.

The study on inheritance pattern, phenotype and nutritional analysis of atgrf2 transgenic rapeseed (brassica napus. L)

The rapeseed (Brassica napus L.) is the third most important economic plant in the world, from rapeseeds to oils and biodiesel. The results of previous studies have determined that possibilities to increase seed yield via increasing the size of the green leaf and the photosynthetic intensity. Therefore, the aims of this study to determine an inheritance pattern of transgene to T1 progeny, to compare phenotype of wild type and transgenic plants and to detect and compare some nutritional values of wild type and transgenic. Rapeseed seed surface was washed with 10% sodium hypochlorite for 10 min and rinse with sterile distilled water 3 times. T1 genetic inheritages were 3:1 to Mendelian ratio means 1 copy number of transgene was integrated into rapeseed genome. The height of AtGRF2 transgenic plants 25% higher than that if wild type plants, long shaft was 37.5%, leaf length was 31.6%, leaf width was 28.1%, and leaf area was increased by 34.8% than wild type plants. The total protein content of the transgenic plants 0.5% higher than that of the whole wild type plant, the total amount of the dietary fiber was the same, and the calcium content was 1.7% lower. About calcium, total ash, organic matter and total fat contents were very little difference. From the results, we concluded that the nutritional value of transgenic and wild type rapeseed plants was not shown significant differences. Atgrf2 ген шилжүүлэн суулгасан рапс (brassica napus l.) -ын удамшил, фенотип, шимт чанарын зарим үзүүлэлтийн судалгаа Хураангуй Рапс (Brassica napus L.) нь дэлхийд 3-рт ордог эдийн засгийн чухал ач холбогдолтой таримал ургамал бөгөөд рапсаас хүнсний тос, биодизел гарган авдаг. Рапсын тосыг үрээс нь ялган авдаг ба ургамлын ногоон навчны хэмжээ, фотосинтезийн эрчмийг нэмэгдүүлснээр үрийн гарц, хэмжээг нэмэгдүүлсэн судалгааны дүнгүүд байдаг. Иймээс энэхүү судалгаагаар ургамлын өсөлтийг идэвхжүүлэгч AtGRF2 (Arabidopsis thaliana growth-regulating factor2) ген шилжүүлэн суулгасан рапс (Brassica napus L.) -ны удамшил, фенотип, шимт чанарын зарим үзүүлэлтийг тодорхойлох зорилго тавилаа. Рапсын үрийн гадаргууг 10%-ийн гипохлорид натрийн уусмалаар 10 мин угааж, ариутгасан нэрмэл усаар 3 удаа зайлж ариутгав. Антибиотикт тэсвэрлэх тохиромжтой хувилбар 30 мкл гигромицинт тэжээлт орчинд Т1 удмын үрийг ургуулж антибиотикт тэсвэрлэх чанараар AtGRF2 генийн удамшлын тооцоолон үзэхэд Т1-д генийн удамшил Менделийн хуулийн дагуу 3:1 байв. AtGRF2 ген шилжин орсон трансген рапсын ургамлын навчны хэмжээг эх ургамалтай харьцуулан үзэхэд трансген ургамлын өндөр хяналтаас 25%-иар, зайдмалын урт 37,5%-иар, зайдмалын тоо 18,8% навчны урт 31,6%-иар, навчны өргөн 28,1%-иар, навчны талбай 34,8%-иар томорсон байна.Трансген рапсанд агуулагдах фосфор, азотгүй хандлаг бодис (АХБ), нийт үнс, органик бодис, нийт тослогийн хэмжээ нь эх ургамлынхаас маш бага зөрөөтэй харин нийт уураг эх ургамлаасаа маш бага буюу 0,5%-иар их, нийт эслэгийн хэмжээ ижил, харин кальцийн хэмжээ 1,7%-иар бага байгаа нь трансген рапс шимт чанарын хувьд эх ургамалтай маш төстэй болохыг харуулж байна. Түлхүүр үг: Гигромицин тэсвэр, gus ген

Development of transgenic Brassica napus with an optimized cry1C* gene for resistance to diamondback moth (Plutella xylostella)

Wang, Y., Zhang, Y., Wang, F., Liu, C. and Liu, K. 2014. Development of transgenic Brassica napus with an optimized cry1C* gene for resistance to diamondback moth (Plutella xylostella). Can. J. Plant Sci. 94: 1501–1506. Bacillus thuringiensis (Bt) cry1Ac gene has been transformed into rapeseed to control diamondback moth (DBM, Plutella xylostella), which is one of the major lepidopteran pests of rapeseed (Brassica napus). However, Cry1A-resistant DBM populations have already developed in the field. Cry1C* is a new synthetic Bt gene based on the original cry1Ca5 sequence through optimizing its codons as well as removing AT-rich sequences and inverted repeats. In our present study, the cry1C* gene was introduced into rapeseed via Agrobacterium-mediated transformation, and a total of 42 transgenic lines were recovered. The results of polymerase chain reaction (PCR) and Southern blot both confirmed the expression of the cry1C* gene in the genomes of the transformants. We also assessed the expression of this foreign gene at the mRNA level in some selected transgenic lines by real-time reverse transcription (RT) PCR analysis. Enzyme-linked immunosorbent assay (ELISA) showed that the Cry1C* expression at the protein level greatly varied among individual transgenic plants, and transgenic line 1C-8 had the highest protein level of 799.32 ng g−1. The transgenic rapeseed plants expressing cry1C* gene showed a high efficacy against DBM. Taken together, the cry1C*-transgenic rapeseed could be employed as a useful germplasm in pest management and in the broad bioinsecticidal spectrum to prevent and postpone the development of pest resistance.