Efficient Genetic Transformation and Regeneration of a Farmer-Preferred Cassava Cultivar From Ghana.

Cassava is an important staple crop that provides food and income for about 700 million Africans. Cassava productivity in Africa is limited by viral diseases, mainly cassava mosaic disease (CMD) and cassava brown streak disease (CBSD). Genetic barriers such as high heterozygosity, allopolyploidy, poor seed set, and irregular flowering constrain the development of virus-resistant cassava varieties conventional breeding.

Genetic Transformation of Recalcitrant Cassava by Embryo Selection and Increased Hormone Levels.

Genetic engineering is considered to be an important tool for the improvement of cassava. Cassava is a highly heterozygous crop species for which conventional breeding is a lengthy and tedious process. Robust transformation is based on Agrobacterium-mediated transformation of friable embryogenic callus (FEC).

Cassava geminivirus agroclones for virus-induced gene silencing in cassava leaves and roots.

Aim: We report the construction of a Virus-Induced Gene Silencing (VIGS) vector and an agroinoculation protocol for gene silencing in cassava ( Crantz) leaves and roots. The African cassava mosaic virus isolate from Nigeria (ACMV-[NOg]), which was initially cloned in a binary vector for agroinoculation assays, was modified for application as VIGS vector. The functionality of the VIGS vector was validated in and subsequently applied in wild-type and transgenic cassava plants expressing the gene under the control of the CaMV 35S promoter in order to facilitate the visualization of gene silencing in root tissues.

Tackling agriculturally relevant diseases in the staple crop cassava (Manihot esculenta).

Cassava is an important staple food crop for millions of people in tropical regions across Africa, South America and Asia. Viral, bacterial and fungal diseases impact cassava yield in all three regions. The viruses causing cassava mosaic disease and cassava brown streak disease have been particularly devastating to cassava production in Africa.

The Arabidopsis B3 domain protein VERNALIZATION1 (VRN1) is involved in processes essential for development, with structural and mutational studies revealing its DNA-binding surface.

The B3 DNA-binding domain is a plant-specific domain found throughout the plant kingdom from the alga Chlamydomonas to grasses and flowering plants. Over 100 B3 domain-containing proteins are found in the model plant Arabidopsis thaliana, and one of these is critical for accelerating flowering in response to prolonged cold treatment, an epigenetic process called vernalization. Despite the specific phenotype of genetic vrn1 mutants, the VERNALIZATION1 (VRN1) protein localizes throughout the nucleus and shows sequence-nonspecific binding in vitro.

High-throughput genomic sequencing of cassava bacterial blight strains identifies conserved effectors to target for durable resistance.

Cassava bacterial blight (CBB), incited by Xanthomonas axonopodis pv. manihotis (Xam), is the most important bacterial disease of cassava, a staple food source for millions of people in developing countries. Here we present a widely applicable strategy for elucidating the virulence components of a pathogen population.

Increased plant volatile production affects oviposition, but not larval development, in the moth Helicoverpa armigera.

It is well established that herbivorous insects respond to changes in plant odour production, but little attention has been given to whether these responses relate to direct fitness costs of plant volatile production on insect growth and survival. Here, we use transgenic Nicotiana tabacum (tobacco) plants that produce relatively large amounts of the volatile (S)-linalool to study whether the responses of egg-laying herbivorous insects to linalool production relate directly to the growth and survival of offspring. In choice tests, fewer eggs were laid on transgenic plants compared with non-transformed controls, indicating that increased linalool emissions have a deterrent effect on Helicoverpa armigera oviposition.

ECT efficacy and treatment course: a systematic review and meta-analysis of twice vs thrice weekly schedules.

Background: Electroconvulsive therapy (ECT) guidelines, across various regulatory bodies, lack consensus as to the optimal frequency of treatment for individual patients. Some authors postulate that twice weekly ECT may have a similar efficacy to thrice weekly, and may have a lower risk of adverse cognitive outcomes. We did a systematic review and a meta-analysis to assess the strength of associations between ECT frequency and depression scores, duration of treatment, number of ECTs, and remission rates.

Albumins and their processing machinery are hijacked for cyclic peptides in sunflower.

The cyclic peptide sunflower trypsin inhibitor 1 (SFTI-1) blocks trypsin and is a promising drug lead and protein engineering scaffold. We show that SFTI-1 and the newfound SFT-L1 are buried within PawS1 and PawS2, precursors for seed storage protein albumins. Proalbumins are matured by asparaginyl endopeptidase, which we show is required to liberate both ends of SFTI-1 as well as to mature PawS1 albumin.

Arabidopsis SET DOMAIN GROUP2 is required for H3K4 trimethylation and is crucial for both sporophyte and gametophyte development.

Histone H3 lysine 4 trimethylation (H3K4me3) is abundant in euchromatin and is in general associated with transcriptional activation in eukaryotes. Although some Arabidopsis thaliana SET DOMAIN GROUP (SDG) genes have been previously shown to be involved in H3K4 methylation, they are unlikely to be responsible for global genome-wide deposition of H3K4me3. Most strikingly, sparse knowledge is currently available about the role of histone methylation in gametophyte development.

Arabidopsis histone methyltransferase SET DOMAIN GROUP8 mediates induction of the jasmonate/ethylene pathway genes in plant defense response to necrotrophic fungi.

As sessile organisms, plants have to endure a wide variety of biotic and abiotic stresses, and accordingly they have evolved intricate and rapidly inducible defense strategies associated with the activation of a battery of genes. Among other mechanisms, changes in chromatin structure are thought to provide a flexible, global, and stable means for the regulation of gene transcription. In support of this idea, we demonstrate here that the Arabidopsis (Arabidopsis thaliana) histone methyltransferase SET DOMAIN GROUP8 (SDG8) plays a crucial role in plant defense against fungal pathogens by regulating a subset of genes within the jasmonic acid (JA) and/or ethylene signaling pathway.

Identification of candidates for cyclotide biosynthesis and cyclisation by expressed sequence tag analysis of Oldenlandia affinis.

Background: Cyclotides are a family of circular peptides that exhibit a range of biological activities, including anti-bacterial, cytotoxic, anti-HIV activities, and are proposed to function in plant defence. Their high stability has motivated their development as scaffolds for the stabilisation of peptide drugs. Oldenlandia affinis is a member of the Rubiaceae (coffee) family from which 18 cyclotides have been sequenced to date, but the details of their processing from precursor proteins have only begun to be elucidated.

The 5' untranslated region of the VR-ACS1 mRNA acts as a strong translational enhancer in plants.

The structure and function of untranslated mRNA leader sequences and their role in controlling gene expression remains poorly understood. Previous research has suggested that the 5' untranslated region (5'UTR) of the Vigna radiata aminocyclopropane-1-carboxylate synthase synthase (VR-ACS1) gene may function as a translational enhancer in plants. To test such hypothesis we compared the translation enhancing properties of three different 5'UTRs; those from the VR-ACS1, the chlorophyll a/b binding gene from petunia (Cab22L; a known translational enhancer) and the Vigna radiata pectinacetylesterase gene (PAE; used as control).

Characterization of a strong, constitutive mung bean (Vigna radiata L.) promoter with a complex mode of regulation in planta.

We report the cloning and characterization in tobacco and Arabidopsis of a Vigna radiata L. (mung bean) promoter that controls the expression of VR-ACS1, an auxin-inducible ACC synthase gene. The VR-ACS1 promoter exhibits a very unusual behavior when studied in plants different from its original host, mung bean.