Molecular and phenotypic characterization of Als1 and Als2 mutations conferring tolerance to acetolactate synthase herbicides in soybean.

Background: Sulfonylurea (SU) herbicides are effective because they inhibit acetolactate synthase (ALS), a key enzyme in branched-chain amino acid synthesis required for plant growth. A soybean line known as W4-4 was developed through rounds of seed mutagenesis and was demonstrated to have a high degree of ALS-based resistance to both post-emergence and pre-emergence applications of a variety of SU herbicides. This report describes the molecular and phenotypic characterization of the Als1 and Als2 mutations that confer herbicide resistance to SUs and other ALS inhibitors.

The P0 gene of Sugarcane yellow leaf virus encodes an RNA silencing suppressor with unique activities.

The Sugarcane yellow leaf virus (SCYLV) P0, a member of the highly heterologous proteins of poleroviruses, is a suppressor of posttranscriptional gene silencing (PTGS) and has additional activities not seen in other P0 proteins. The P0 protein in previously tested poleroviruses (Beet western yellows virus and Cucurbit aphid-borne yellows virus), suppresses local, but not systemic, PTGS induced by both sense GFP and inverted repeat GF using its F-box-like domain to mediate destabilization of the Argonaute1 protein. We now report that the SCYLV P0 protein not only suppressed local PTGS induced by sense GFP and inverted repeat GF in Nicotiana benthamiana, but also triggered a dosage dependent cell death phenotype in infiltrated leaves and suppressed systemic sense GFP-PTGS.

Efficient transient expression of human GM-CSF protein in Nicotiana benthamiana using potato virus X vector.

The human granulocyte macrophage colony-stimulating factor (GM-CSF) is a glycoprotein with important clinical applications for the treatment of neutropenia and aplastic anemia and reducing infections associated with bone marrow transplants. We evaluated the potential for using a potato virus X (PVX) viral vector system for efficient expression of the biologically functional GM-CSF protein in Nicotiana benthamiana leaves. The GM-CSF gene was cloned into PVX viral expression vector, driven with the CaMV 35S promoter.

Cloning and characterization of a FLORICAULA/LEAFY ortholog, PFL, in polygamous papaya.

The homologous genes Floricaula (FLO) in Antirrhinum and LEAFY (LFY) in Arabidopsis are known to regulate the initiation of flowering in these two distantly related plant species. These genes are necessary also for the expression of downstream genes that control floral organ identity. We used Arabidopsis LFY cDNA as a probe to clone and sequence a papaya ortholog of LFY, PFL.

Production of biologically active GM-CSF in sugarcane: a secure biofactory.

Over 300 transgenic sugarcane plants representing approx. 200 independent lines producing the human cytokine granulocyte macrophage colony stimulating factor (GM-CSF) were analyzed for recombinant protein accumulation and activity levels. Expression constructs differed in use of the maize polyubiquitin 1, Mubi-1, or the sugarcane polyubiquitin 9, SCubi9, promoters; presence or absence of a C-terminal HDEL tag for ER retention; and presence or absence of a 6X Histidine tag for metal ion affinity purification.

Effective selection of transgenic papaya plants with the PMI/Man selection system.

The selectable marker gene phospho-mannose isomerase (pmi), which encodes the enzyme phospho-mannose isomerase (PMI) to enable selection of transformed cell lines on media containing mannose (Man), was evaluated for genetic transformation of papaya (Carica papaya L.). We found that papaya embryogenic calli have little or no PMI activity and cannot utilize Man as a carbon source; however, when calli were transformed with a pmi gene, the PMI activity was greatly increased and they could utilize Man as efficiently as sucrose.

Comparative expression analysis of two sugarcane polyubiquitin promoters and flanking sequences in transgenic plants.

GUS (uidA) reporter gene expression for two sugarcane polyubiquitin promoters, ubi4 and ubi9, was compared to expression from the maize Ubi-1 promoter in stable transgenic rice (only ubi9) and sugarcane (ubi4 and ubi9). Ubi9 drove high-level GUS expression, comparable to the maize Ubi-1 promoter, in both callus and regenerated plants of rice transformed by Agrobacterium. This high level expression was inherited in R1 plants.