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The optimal timing of transition from vegetative to floral reproductive phase is critical for plant productivity and agricultural yields. Light plays a decisive role in regulating this transition. The B‐box (BBX) family of transcription factors regulates several light‐mediated developmental processes in plants, including flowering. Here, we identify a previously uncharacterized group II BBX family member, BBX13/COL15, as a negative regulator of flowering under long‐day conditions. BBX13 is primarily expressed in the leaf vasculature, buds, and flowers, showing a similar spatial expression pattern to the major flowering time regulators CO and FT. bbx13 mutants flower early, while BBX13‐overexpressors exhibit delayed flowering under long days. Genetic analyses showed that BBX13 acts upstream to CO and FT and negatively regulates their expression. BBX13 physically interacts with CO and inhibits the CO‐mediated transcriptional activation of FT. In addition, BBX13 directly binds to the CORE2 motif on the FT promoter, where CO also binds. Chromatin immunoprecipitation data indicates that BBX13 reduces the in vivo binding of CO on the FT promoter. Through luciferase assay, we found that BBX13 inhibits the CO‐mediated transcriptional activation of FT. Together, these findings suggest that BBX13/COL15 represses flowering in Arabidopsis by attenuating the binding of CO on the FT promoter. Summary statement: BBX13, a previously uncharacterized protein in the B‐Box family of transcription factors, negatively regulates flowering time in Arabidopsis thaliana. BBX13 physically and genetically interacts with CO and inhibits the CO‐mediated transcriptional activation of FT. [ABSTRACT FROM AUTHOR]

The night‐flowering Jasmine, Nyctanthes arbor‐tristis also known as Parijat, is a perennial woody shrub belonging to the family of Oleaceae. It is popular for its fragrant flowers that bloom in the night and is a potent source of secondary metabolites. However, knowledge about its genome and the expression of genes regulating flowering or secondary metabolite accumulation is lacking. In this study, we generated whole genome sequencing data to assemble the first de novo assembly of Parijat and use it for comparative genomics and demographic history reconstruction. The temporal dynamics of effective population size (Ne) experienced a positive influence of colder climates suggesting the switch to night flowering may have provided an evolutionary advantage. We employed multi‐tissue transcriptome sequencing of floral stages/parts to obtain insights into the transcriptional regulation of nocturnal flower development and the production of volatiles/metabolites. Tissue‐specific transcripts for mature flowers revealed key players in circadian regulation and flower development, including the auxin pathway and cell wall modifying genes. Furthermore, we identified tissue‐specific transcripts responsible for producing numerous secondary metabolites, mainly terpenoids and carotenoids. The diversity and specificity of Terpene Synthase (TPS) and CCDs (Carotenoid Cleavage Deoxygenases) mediate the bio‐synthesis of specialised metabolites in Parijat. Our study establishes Parijat as a novel non‐model species to understand the molecular mechanisms of nocturnal blooming and secondary metabolite production. [ABSTRACT FROM AUTHOR]

Summary: In plants, the switch to autotrophic growth involves germination followed by postgermination seedling establishment. When environmental conditions are not favorable, the stress hormone abscisic acid (ABA) signals plants to postpone seedling establishment by inducing the expression of the transcription factor ABI5. The levels of ABI5 determine the efficiency of the ABA‐mediated postgermination developmental growth arrest. The molecular mechanisms regulating the stability and activity of ABI5 during the transition to light are less known.Using genetic, molecular, and biochemical approach, we found that two B‐box domain containing proteins BBX31 and BBX30 alongwith ABI5 inhibit postgermination seedling establishment in a partially interdependent manner.BBX31 and BBX30 are also characterized as microProteins miP1a and miP1b, respectively, based on their small size, single domain, and ability to interact with multidomain proteins. miP1a/BBX31 and miP1b/BBX30 physically interact with ABI5 to stabilize it and promote its binding to promoters of downstream genes. ABI5 reciprocally induces the expression of BBX30 and BBX31 by directly binding to their promoter.ABI5 and the two microProteins thereby form a positive feedback loop to promote ABA‐mediated developmental arrest of seedlings. [ABSTRACT FROM AUTHOR]

For the past several decades, dengue fever has been emerging in epidemic proportions in several regions of the world. During August–September 2019, an increasing number of fever cases were being reported from some areas of North 24 Parganas district of West Bengal, India. Accordingly, outbreak investigation of fever cases from these affected areas of Bongoan, Barasat, and Habra was carried out. To characterize clinical and biochemical features of fever cases as well as to investigate the utility of CRP as a Dengue severity marker in resource‐limited settings. We systematically enrolled 108 patients from the affected region of North 24 Parganas. Standard diagnostic assays along with routine serological and biochemical parameters were performed. Of the 108 patients, 77 (71%) were confirmed with Dengue infection followed by 22 (20%) DENV seronegative and 9 (8%) coinfected DENV cases. Among the 77 confirmed Dengue patients, 53 (69%) had primary infection while 24 (31%) had secondary infection. Among the DENV clinical symptoms, fever (r = 0.50; p = 0.004), headache (r = 0.40; p = 0.03) and abdominal pain (r = −0.40; p = 0.02) were found to bear significant correlation with DENV viral load. The predominant circulating serotype was found to be DENV2. CRP Dengue severity cut‐off level of 10.15 mg/L (AUC: 0.85; 86% sensitivity, 77% specificity) was obtained. CRP had correlation with viral load (r = 0.4, p = 0.05) within febrile phase of infection. The performance of biomarkers can be influenced by local epidemiology, geography, and several patient factors, therefore, CRP Dengue severity cut‐off value may be region‐specific. This study for the first time attempts to estimate CRP Dengue severity cut‐off value based on routine immunoturbidometric evaluation from Dengue Hyperendemic zones of North 24 Parganas, West Bengal, Eastern India. [ABSTRACT FROM AUTHOR]

Summary: Greening of cotyledons during de‐etiolation is critical for harvesting light energy and sustaining plant growth. PIF3 and HY5 antagonistically regulate protochlorophyllide synthesis in the dark. However, the mechanism by which the PIF3/HY5 module regulates genes involved in protochlorophyllide synthesis is not clear.Using genetic, molecular and biochemical techniques we identified that the B‐BOX protein BBX11 acts directly downstream of PIF3 and HY5 to transcriptionally modulate genes involved in protochlorophyllide synthesis.Dark‐grown bbx11 and 35S:BBX11 seedlings exhibit an enhanced and reduced ability to green, respectively, when exposed to light. Transcript levels of HEMA1 and CHLH are upregulated in 35S:BBX11 seedlings that accumulate high levels of protochlorophyllide in the dark and undergo photobleaching upon illumination. PIF3 inhibits BBX11 in the dark by directly binding to its promoter. bbx11 suppresses the cotyledon greening defect of pif3 after prolonged dark, indicating that the PIF3‐mediated regulation of greening is dependent on BBX11. The enhanced greening of hy5 is also suppressed in hy5 lines overexpressing BBX11. In light, HY5 directly binds to the promoter of BBX11 and activates its expression to regulate BBX11‐mediated hypocotyl inhibition.We show that a PIF3/HY5 module regulates BBX11 expression in opposite ways to optimise protochlorophyllide accumulation in the dark and promote photomorphogenesis in light. [ABSTRACT FROM AUTHOR]

The prevalence of aluminum ions (Al3+) under acidic soil conditions inhibits primary root elongation and hinders plant growth and productivity. Al3+ alters the membrane potential, displaces critical ions in the apoplast and disrupts intracellular ionic concentrations by targeting membrane‐localized solute transporters. Here, we provide an overview of how Al3+ affects the activities of several solute transporters especially in the root. High Al3+ level impairs the functions of potassium (K+), calcium (Ca2+), magnesium (Mg2+), nitrate (NO3−) and ammonium (NH4+) transporters. We further discuss the role of some key transporters in mediating Al tolerance either by exclusion or sequestration. Anion channels responsible for organic acid efflux modulate the sensitivity to Al3+. The ALUMINUM ACTIVATED MALATE TRANSPORTER (ALMT) and MULTIDRUG AND TOXIC COMPOUND EXTRUSION (MATE) family of transporters exude malate and citrate, respectively, to the rhizosphere to alleviate Al toxicity by Al exclusion. The ABC transporters, aquaporins and H+‐ATPases perform vacuolar sequestration of Al3+, leading to aluminum tolerance in plants. Targeting these solute transporters in crop plants can help generating aluminum‐tolerant crops in future. [ABSTRACT FROM AUTHOR]

Summary: Abscisic acid (ABA) plays a crucial role in plant development, regulating germination, seedling development and stomatal movements, especially under adverse conditions. Light interacts with the ABA signalling pathway to fine tune these processes. Here, we provide an overview of the recent investigations on ABA–light interplay during early plant development after germination. We discuss the multilayered and reciprocal interactions between ABA signalling components and several light signalling modulators, including photoreceptors, transcription factors and posttranslational modifiers. ABSCISIC ACID INSENSITIVE5 acts as a central convergence point for these interactions during postgermination seedling development. ABA also regulates the adaptation of seedlings to challenging light environments. Furthermore, we enlist the role of ABA–light cross‐talk in regulating seedling establishment in crops and highlight open questions for future investigations. [ABSTRACT FROM AUTHOR]

Light plays an important role in plants' growth and development throughout their life cycle. Plants alter their morphological features in response to light cues of varying intensity and quality. Dedicated photoreceptors help plants to perceive light signals of different wavelengths. Activated photoreceptors stimulate the downstream signaling cascades that lead to extensive gene expression changes responsible for physiological and developmental responses. Proteins such as ELONGATED HYPOCOTYL5 (HY5) and CONSTITUTIVELY PHOTOMORPHOGENIC 1 (COP1) act as important factors which modulate light‐regulated gene expression, especially during seedling development. These factors function as central regulatory intermediates not only in red, far‐red, and blue light pathways but also in the UV‐B signaling pathway. UV‐B radiation makes up only a minor fraction of sunlight, yet it imparts many positive and negative effects on plant growth. Studies on UV‐B perception, signaling, and response in plants has considerably surged in recent times. Plants have developed different strategies to use UV‐B as a developmental cue as well as to withstand high doses of UV‐B radiation. Plants' responses to UV‐B are an integration of its cross‐talks with both environmental factors and phytohormones. This review outlines the current developments in light signaling with a major focus on UV‐B‐mediated plant growth regulation. [ABSTRACT FROM AUTHOR]

Summary: Under acute stress conditions, precocious seedling development may result in the premature death of young seedlings, before they switch to autotrophic growth. The phytohormone abscisic acid (ABA) inhibits seed germination and post‐germination seedling establishment under unfavorable conditions. Various environmental signals interact with the ABA pathway to optimize these early developmental events under stress. Here, we show that light availability critically influences ABA sensitivity during early seedling development. In dark conditions, the ABA‐mediated inhibition of post‐germination seedling establishment is strongly enhanced. COP1, a central regulator of seedling development in the dark, is necessary for this enhanced post‐germination ABA sensitivity in darkness. Despite their slower germination, cop1 seedlings establish faster than wild type in the presence of ABA in both light and dark. PHY and CRY photoreceptors that inhibit COP1 activity in light modulate ABA‐mediated inhibition of seedling establishment in light. Genetically, COP1 acts downstream to ABI5, a key transcriptional regulator of ABA signaling, and does not influence the transcriptional and protein levels of ABI5 during the early post‐germination stages. COP1 promotes post‐germination growth arrest independent of the antagonistic interaction between ABA and cytokinin signaling pathways. COP1 facilitates the binding of ABI5 on its target promoters and the ABA‐mediated upregulation of these target genes is reduced in cop1‐4. Together, our results suggest that COP1 positively regulates ABA signaling to inhibit post‐germination seedling establishment under stress. Significance Statement: Abscisic acid (ABA)‐induced inhibition of precocious seedling development is important for the survival of plants under stress conditions. We show that the light signaling protein COP1 positively regulates ABA signaling by facilitating the binding of ABI5 on its target promoters and thus inhibiting seedling establishment after germination under stress. [ABSTRACT FROM AUTHOR]

MATE (multidrug and toxic compound extrusion) transporters play multiple roles in plants including detoxification, secondary metabolite transport, aluminium (Al) tolerance, and disease resistance. Here we identify and characterize the role of the Arabidopsis MATE transporter DETOXIFICATION30. AtDTX30 regulates auxin homeostasis in Arabidopsis roots to modulate root development and Al‐tolerance. DTX30 is primarily expressed in roots and localizes to the plasma membrane of root epidermal cells including root hairs. dtx30 mutants exhibit reduced elongation of the primary root, root hairs, and lateral roots. The mutant seedlings accumulate more auxin in their root tips indicating role of DTX30 in maintaining auxin homeostasis in the root. Al induces DTX30 expression and promotes its localization to the distal transition zone. dtx30 seedlings accumulate more Al in their roots but are hyposensitive to Al‐mediated rhizotoxicity perhaps due to saturation in root growth inhibition. Increase in expression of ethylene and auxin biosynthesis genes in presence of Al is absent in dtx30. The mutants exude less citrate under Al conditions, which might be due to misregulation of AtSTOP1 and the citrate transporter AtMATE. In conclusion, DTX30 modulates auxin levels in root to regulate root development and in the presence of Al indirectly modulates citrate exudation to promote Al tolerance. DTX30 modulates auxin level in root to regulate root development and indirectly promotes citrate exudation to alleviate aluminium toxicity. [ABSTRACT FROM AUTHOR]

ROOT HAIR DEFECTIVE SIX-LIKE4 ( RSL4) is necessary and sufficient for root hair elongation in Arabidopsis thaliana. Root hair length is determined by the duration for which RSL4 protein is present in the developing root hair. The aim of this research was to identify genes regulated by RSL4 that affect root hair growth., To identify genes regulated by RSL4, we identified genes whose expression was elevated by induction of RSL4 activity in the presence of an inhibitor of translation., Thirty-four genes were identified as putative targets of RSL transcriptional regulation, and the results suggest that the activities of SUPPRESSOR OF ACTIN ( SAC1), EXOCSYT SUBUNIT 70A1 ( EXO70A1), PEROXIDASE7 ( PRX7) and CALCIUM- DEPENDENT PROTEIN KINASE11 ( CPK11) are required for root hair elongation., These data indicate that RSL4 controls cell growth by controlling the expression of genes encoding proteins involved in cell signalling, cell wall modification and secretion. [ABSTRACT FROM AUTHOR]

ABSTRACT Background The purpose of this study was to compare sentinel node biopsy (SNB) and ultrasound-guided fine-needle aspiration cytology (FNAC) for preoperative evaluation of the N0 neck in T1 to T2 oral cavity squamous cell carcinoma (SCC). Methods Fifty-one consecutive patients with T1 to T2 N0 oral cavity SCC were included in this study. Preoperative ultrasound was performed in all patients. Ultrasound-guided FNAC was performed in patients in whom the ultrasound result was reported as indeterminate or positive. SNB was done in all patients followed by elective neck dissection (END). Histopathology of END was considered as the gold standard for all statistical analysis. Results The incidence of occult metastasis was 26.4%. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were 71.4%, 100%, 100%, and 90.2% for SNB and 14.3%, 100%, 100%, and 76.5% for ultrasound-guided FNAC. Conclusion Ultrasound-guided FNAC lacked sufficient accuracy to detect occult metastases. SNB is a reliable method to detect occult metastasis that has potential to replace END. © 2014 Wiley Periodicals, Inc. Head Neck 37: 1504-1508, 2015 [ABSTRACT FROM AUTHOR]

Background The cost-effectiveness of the frozen section for assessment of margin in head and neck squamous cell carcinoma (HNSCC) is still contentious. The purpose of this study was to evaluate whether gross examination of margin is an alternative to frozen section. Methods It was a prospective observational study in 145 consecutive patients undergoing surgery for HNSCC. Surgical margins were first assessed by the surgeons with a metallic scale. All specimens were then examined using frozen section and permanent section. Results Overall, 83% of inadequate margins were detected by frozen section. The chances of inadequate margin were very low if gross surgical margin were 7 mm or more. Gross examination alone (with 7 mm as cutoff) predicted 88% of the inadequate surgical margin. There was no difference in precision of frozen section vis-à-vis gross examination with 7 mm cut off ( p ≤ .8). Conclusion Achievement of 7 mm surgical margin measured by a surgeon obviates the need for frozen section. © 2013 Wiley Periodicals, Inc. Head Neck 36: 557-563, 2014 [ABSTRACT FROM AUTHOR]

Background Oral cancer is the most common cancer in Indian males and is the third most common cancer in Indian females. Tobacco, alcohol, areca nut, and human papillomavirus (HPV) are the common etiologic factors. Each of these agents follows a unique model of carcinogenesis that leads to a certain distinct presentation and behavior. For example, HPV is strongly associated with oropharyngeal cancers in younger age and is known to have a better outcome and specific histopathologic characteristics. A high incidence of oral submucous fibrosis (OSMF) is linked to areca nut (group 1 human carcinogen) chewing in the Indian subcontinent. Methods We prospectively studied 371 consecutive patients with proven squamous cell carcinoma of the oral cavity. Of these, 112 patients had oral cancer with OSMF and 259 had oral cancer without OSMF. All patients underwent standard management and their clinicopathologic findings were recorded. Results We found that patients of oral cancer with OSMF are younger males with better prognostic factors such as better grade of tumor differentiation, lesser incidence of nodal metastases, and extracapsular spread. This difference was maintained even after matching for stage. We also report that presence of OSMF is an independent factor influencing nodal metastases. Conclusions Based on these findings we propose that oral cancers with OSMF constitute a clinicopathologically distinct disease. Since all patients with OSMF had chewed areca nut with or without smokeless tobacco, we believe that the differences in the 2 groups emanate from differential mechanisms of areca nut carcinogenesis. © 2012 Wiley Periodicals, Inc. Head Neck 35: 1404-1409, 2013 [ABSTRACT FROM AUTHOR]