Plant Molecular Biology Reporter

Nuclear run-on transcription assays allow researchers to determine if a gene is regulated at the transcriptional level. Existing methods to perform this procedure involve the application of a large variety of biochemical reagents, numerous steps, and time-consuming procedures. Here we report a method to perform this assay on plant tissue that involves a minimal number of reagents and steps, is time-efficient, and produces clean definitive results within 24 h.

If chloroplasts purified on sucrose step gradients are treated for 10 min at 4°C with 2 M NaCl, followed by a 1000-g centrifugation, nuclear DNA contamination is reduced 1.5 to 3 fold as estimated by densitometry.

In this report, we present data on OsSDS1 (Oryza sativa L. salt and drought sensitive gene 1)—an uncharacterized gene isolated from rice Pei’ai 64S (O. sativa L.). Expression of OsSDS1 was strongly up-regulated by a wide spectrum of stresses, including cold, drought, and heat, in different tissues at different developmental stages of rice, as revealed by both microarray and quantitative RT-PCR analyses. Subcellular localization revealed that an OsSDS1: GFP fusion protein was distributed to the nucleus. Expression of OsSDS1 conferred decreased tolerance to salt and drought in Arabidopsis thaliana, accompanied by altered expression of stress-responsive genes and altered K+/Na+ ratio. The results suggest that OsSDS1 may act as a negative regulator of salt and drought tolerance in plants.

Plants are sessile organisms that have to cope with different environmental stresses during their life cycle. Photosystem II is one of the most labile processes affected by abiotic stress. The chloroplast small heat shock proteins (Cp-sHSPs) are known to protect photosystem II and thylakoid membranes during heat stress. Previously, we reported several cis-regulatory elements in the promoter regions of Cp-sHSPs of Chenopodium album (Shakeel et al., Plant Physiol Biochem 49:898–908, 2011) and differential regulation of a novel Cp-sHSP family member, CaHSP26.13p, under heat and metal stress (Haq et al., Plant Cell Reports 31:1943–1957, 2012). To further explore the role of Cp-sHSPs in plant stress tolerance, we subjected C. album plants to salt, drought, or cold stress and characterized the accumulation of Cp-sHSP transcripts. Full-length Cp-sHSP transcripts were analyzed for the presence of characteristic domains of Cp-sHSPs and compared with previously known Cp-sHSP homologs and orthologs. Analysis showed that the CaHSP26.13p transcript is differentially regulated under heat, metal, cold, drought, or salt stress. Immunoblot analysis revealed the presence of the precursor proteins (∼26 kDa) synthesized from this transcript. The expression level varied depending on the conditions. Generally, transcript and protein levels were not correlated. This study demonstrates that a single C. album Cp-sHSP had multiple roles under a variety of environmental stresses.

We developed a procedure to isolate DNA from dried corncobs. This DNA was amplified successfully by PCR, producing well-defined bands in response to specific primers. The SSR patterns between cob and leaf DNA of the same inbred line were found to be identical, indicating that the DNA in the cob cells had not degraded during senescence.

Salvia miltiorrhiza (SM), a widely popular Chinese herb, is grown in various regions in China. Identifying SMs grown in different provinces of China is difficult, and therefore genotyping these collections would be highly valuable. Based on the techniques of sequence-related amplified polymorphism and target region amplified polymorphism, a novel PCR-based molecular marker technique called conserved region amplification polymorphism (CoRAP) is reported in this study to genotype SMs. The CoRAP technique is based on the use of two primers: fixed and arbitrary primers. The former is derived from target EST sequences deposited in Genbank; while, the core sequence (CACGC) of the latter is a conserved region found in most introns. In the present study, we utilized CoRAP to genotype SMs from different geographical origins. PCR amplification is performed for 30 cycles at an annealing temperature of 52°C. Each PCR reaction has generated as many as 30–50 fragments of 50 to 1,000 bp in size. The successful DNA genotyping of SMs by CoRAP was achieved. This new genotyping method is rapid, efficient, and reproducible.

Plant pararetroviruses (PRVs; family Caulimovirida) are non-enveloped double-stranded DNA viruses having either isometric or bacilliform virion. According to the current taxonomy, the family Caulimoviridae consists of ten genera with two newly added genera Dioscovirus and Vaccinivirus. PRVs have a genome size between 7 and 9 kilobase pairs and differ mainly based on the number of open reading frames (ORFs; 1 to 8) in each genus. These ORFs encode many functional proteins that help the virus to survive within the host cell. They are transmitted by aphids, mealy bugs, or leafhoppers. These viruses have a wide geographical distribution and infect a broad range of monocotyledonous and dicotyledonous plant species, making their early detection and control a paramount requirement. The transcriptional unit (promoter) of the PRV genome has become an interesting “modular cassette” to the molecular biologist worldwide for fine-tuning of gene expression in plants. The present review highlights the current taxonomy, genome structure, transmission, and diagnosis of pararetroviruses and how the “modular cassette” would help the modern biotechnology-based translational research.