The tomato EAR-motif repressor, SlERF36, accelerates growth transitions and reduces plant life cycle by regulating GA levels and responses.

Faster vegetative growth and early maturity/harvest reduce plant life cycle time and are important agricultural traits facilitating early crop rotation. GA is a key hormone governing developmental transitions that determine growth speed in plants. An EAR-motif repressor, SlERF36 that regulates various growth transitions, partly through regulation of the GA pathway and GA levels, was identified in tomato. Suppression of SlERF36 delayed germination, slowed down organ growth and delayed the onset of flowering time, fruit harvest and whole-plant senescence by 10-15 days. Its over-expression promoted faster growth by accelerating all these transitions besides increasing organ expansion and plant height substantially. The plant life cycle and fruit harvest were completed 20-30 days earlier than control without affecting yield, in glasshouse as well as net-house conditions, across seasons and generations. These changes in life cycle were associated with reciprocal changes in expression of GA pathway genes and basal GA levels between suppression and over-expression lines. SlERF36 interacted with the promoters of two GA2 oxidase genes, SlGA2ox3 and SlGA2ox4, and the DELLA gene, SlDELLA, reducing their transcription and causing a 3-5-fold increase in basal GA3/GA4 levels. Its suppression increased SlGA2ox3/4 transcript levels and reduced GA3/GA4 levels by 30%-50%. SlERF36 is conserved across families making it an important candidate in agricultural and horticultural crops for manipulation of plant growth and developmental transitions to reduce life cycles for faster harvest.

SlDREB3, a negative regulator of ABA responses, controls seed germination, fruit size and the onset of ripening in tomato.

SlDREB3 was identified as a ripening up-regulated gene of the AP2/ERF-domain family of transcription factors. Its manipulation affects processes primarily governed by ABA. It negatively regulates ABA responses in tomato by altering ABA levels/signaling and is, in turn, negatively regulated by ABA. SlDREB3 over-expression lines show higher transcript levels of the ABA metabolism genes CYP707A3 and UGT75C1 and an 85% reduction in ABA levels leading to early seed germination. In contrast, suppression lines show decreased CYP707A3/UGT75C1 expression, 3-fold higher ABA levels and delayed germination. The expression of other ABA signaling and response genes is also affected. Suppression of SlDREB3 accelerates the onset of ripening by 4-5 days while its over-expression delays it and also reduces final fruit size. SlDREB3 manipulation effects large scale changes in the fruit transcriptome with suppression lines showing early increase in ABA levels and activation of most ripening pathway genes that govern ethylene, carotenoids and softening. Strikingly, key transcription factors like CNR, NOR, RIN, FUL1, governing ethylene-dependent and ethylene-independent aspects of ripening, are activated early upon SlDREB3 suppression suggesting their control by ABA. The studies identify SlDREB3 as a negative regulator of ABA responses across tissues and a key ripening regulator controlling ethylene-dependent and ethylene-independent aspects.

Expression of the SIN3 homologue from banana, MaSIN3, suppresses ABA responses globally during plant growth in Arabidopsis.

The SIN3 family of co-repressors is a family of highly conserved eukaryotic repressor proteins that regulates diverse functions in yeasts and animals but remains largely uncharacterized functionally even in plants like Arabidopsis. The sole SIN3 homologue in banana, MaSIN3, was identified as a 1408 amino acids, nuclear localized protein conserved to other SIN3s in the PAH, HID and HCR domains. Interestingly, MaSIN3 over-expression in Arabidopsis mimics a state of reduced ABA responses throughout plant development affecting growth processes such as germination, root growth, stomatal closure and water loss, flowering and senescence. The reduction in ABA responses is not due to reduced ABA levels but due to suppression of expression of several transcription factors mediating ABA responses. Transcript levels of negative regulators of germination (ABI3, ABI5, PIL5, RGL2 and RGL3) are reduced post-imbibition while those responsible for GA biosynthesis are up-regulated in transgenic MaSIN3 over-expressers. ABA-associated transcription factors are also down-regulated in response to ABA treatment. The HDAC inhibitors, SAHA and sodium butyrate, in combination with ABA differentially suppress germination in control and transgenic lines suggesting the recruitment by MaSIN3 of HDACs involved in suppression of ABA responses in different processes. The studies provide an insight into the ability of MaSIN3 to specifically affect a subset of developmental processes governed largely by ABA.

Ectopic expression of a tomato DREB gene affects several ABA processes and influences plant growth and root architecture in an age-dependent manner.

Regulation of whole plant growth and adaptive responses by abscisic acid is complex, requires multiple regulators and largely unknown in plants other than Arabidopsis. We show that over-expression of the tomato SlDREB3/SlERF.H12 (DEHYDRATION RESPONSE ELEMENT BINDING PROTEIN3/ETHYLENE RESPONSE FACTOR. H12) gene can negatively affect many ABA-governed processes across tissues. Its expression leads to early germination in presence of ABA and in response to mannitol, NaCl and glucose. Its expression delays ABA-mediated leaf senescence and natural senescence leading to an increase in plant life by about 20days. Transgenic SlDREB3 lines show reduced ABA-mediated inhibition of conductance and transpiration and a greater sensitivity to water stress. Reduction in sensitivity to ABA-mediated stomatal closure leads to higher photosynthetic rates in transgenic plants than controls. Consequently, transgenic SlDREB3 plants produce a larger number of capsules and greater number of seeds with the increase in yield ranging from 18 to 35% in different seasons under well-watered conditions. Root growth, but not shoot growth, also undergoes a profound increase of about 50% in transgenic SlDREB3 lines. The increase occurs in an age-dependent manner with the most prominent changes being observed between 1.5 and 2.5 months in several independent experiments in different years. SlDREB3 thus seems to govern several ABA-regulated processes across tissues, partly through control over ABA levels. It may encode a factor that is most likely a component of the central ABA response machinery.

Ultramorphological characteristics of immature stages of a forensically important fly Parasarcophaga ruficornis (Fabricius) (Diptera: Sarcophagidae).

Ultrastructure of all larval instars and puparium of Parasarcophaga ruficornis, a common flesh fly species in India, is presented using light microscopy and scanning electron microscopy for the first time. The principal diagnostic characters, i.e. the cephalopharyngeal apparatus, the cephalic segment, structure and orientation of spines, pupal respiratory horns, the structures of both anterior and posterior spiracles are illustrated and discussed. Information presented herein can be useful during forensic investigations involving this fly species.

Off-pump coronary artery bypass: the Sudbury experience.

OBJECTIVE: To examine factors relating to outcomes with off-pump coronary artery bypass (OPCAB) and to assess methods to improve the effectiveness of this approach SETTING: A small northern Ontario community hospital where surgical assistance, nursing familiarity with OPCAB and even anesthesiologist comfort varied DESIGN: Prospective collection of data with incremental audit of results and retrospective analysis of events METHODS: One hundred twenty-four consecutive patients, operated on by the same surgeon between April 1996 and June 2002, were selected on the basis of coronary anatomy. Progressively more complex multivessel revascularization, including that to the posterior wall, was undertaken over the course of the study period. Every attempt was made not to compromise use of arterial conduits, quality of anastomoses or completeness of revascularization. This represents the 'learning curve' of this study. MAIN RESULTS: Approximately 6% of patients developed a hemodynamic crisis requiring acute on-pump conversion. This tended to occur in patients undergoing complex multivessel OPCAB surgery and was associated with subsequent increased blood transfusion rate, operative time and mortality (2.8%), and poorer angiographic graft patency. This has led to a more cautious strategy including making the decision to proceed with OPCAB only after intraoperative assessment. CONCLUSION: 'Simple' OPCAB on easily accessible coronary arteries resulted in excellent early outcomes. Complex multivessel OPCAB for triple vessel disease involving difficult to access arteries was more demanding with higher perioperative complications and less effectiveness. Early enthusiasm for complex multivessel surgery has been gradually replaced with a more conservative use of OPCAB with improved intraoperative procedures, both of which have led to more favourable outcomes.