Identification of transcription factors controlling cell wall invertase gene expression for reproductive development via bioinformatic and transgenic analyses.

Cell wall invertase (CWIN) hydrolyses sucrose into glucose and fructose in the extracellular matrix and plays crucial roles in assimilate partitioning and sugar signalling. However, the molecular regulators controlling CWIN gene transcription remain unknown. As the first step to address this issue, we performed bioinformatic and transgenic studies, which identified a cohort of transcription factors (TFs) modulating CWIN gene expression in Arabidopsis thaliana. Comprehensive bioinformatic analyses identified 18 TFs as putative regulators of the expression of AtCWIN2 and AtCWIN4 that are predominantly expressed in Arabidopsis reproductive organs. Among them, MYB21, ARF6, ARF8, AP3 and CRC were subsequently shown to be the most likely regulators of CWIN gene expression based on molecular characterization of the respective mutant of each candidate TF. More specifically, the obtained data indicate that ARF6, ARF8 and MYB21 regulate CWIN2 expression in the anthers and CWIN4 in nectaries, anthers and petals, whereas AP3 and CRC were determined primarily to regulate the transcriptional activity of CWIN4. TF-promoter interaction assays demonstrated that ARF6 and ARF8 directly control CWIN2 and CWIN4 transcription with AP3 activating CWIN4. The involvement of ARF8 in regulating CWIN4 expression was further supported by the finding that enhanced CWIN4 expression partially recovered the short silique phenotype displayed by the arf8-3 mutant. The identification of the five TFs regulating CWIN expression serves as a launching pad for future studies to dissect the upstream molecular network underpinning the transcription of CWINs and provides a new avenue, potentially, to engineer assimilate allocation and reproductive development for improving seed yield.

Empirical Antibiotic for Diabetic Foot Infection in Indonesian Tertiary Hospital, Is It Time to Rethink the Options?

BACKGROUND: The choice of empiric antibiotics in Diabetic Foot Infection (DFI) is a key to successful therapy. Meanwhile, the management of DFI in Indonesia is  based on guideline originating from western countries which have different bacteriological patterns. Therefore, this study aimed to describe the bacterial and antibiotic susceptibility pattern on DFI which potentially contribute to better antibiotics selection guidelines. METHODS: This was a cross-sectional descriptive study conducted using consecutive sampling with DFI patients admitted in the emergency room and wards of Hasan Sadikin Hospital between February and July 2020. Tissue samples were obtained from all wounds, while antibiotic susceptibility tests were carried out on the culture results. RESULTS: A total of 65 bacterial growths were obtained from 45 enrolled patients. Gram-negative bacteria dominated with 54 growths (83.07%) including Klebsiela pneumonia 13 (20%) as the most common. Furthermore, antibiotics with good susceptible (> 80%) against Gram-negative bacteria are the carbapenemes (meropenem and ertapenem) and amikacin. The multi drug resistant bacteria were found in 18 growths (27.7%), which include ESBL, Carbapenemase producing bacteria, and MRSA. However, there were no susceptibility pattern differences between patients with ulcer duration above or below 2 months, higher grade wound (Wagner 4 and 5) and lower, as well as patients with previous or no antibiotic history. CONCLUSION: The growth of Gram-negative bacteria dominated DFI with limited susceptibility to the empirical first-line antibiotics in the known international guidelines. Therefore, there is a need to reconsider the algorithm for selecting empirical antibiotics and management of DFI which is appropriate in our current condition.

Looking into 'hair tonics' for cotton fiber initiation.

Cotton fiber is the most important source of cellulose for the global textile industry. These hair-like single-celled trichomes develop from ovule epidermis. They are classified into long spinnable lint and short fuzz. A key objective in the cotton industry is to breed elite cultivars with fuzzless seeds carrying high lint yield. Molecular basis underlying lint and fuzz initiation remains obscure. Recent studies indicate fiber initiation is under the control of MYB-bHLH-WDR (MBW) transcription factor complex. Based on molecular genetic studies and gene expression patterns linking fiber phenotypes, we propose that specific but different sets of MBW genes are required to precisely regulate the initiation of the lint and fuzz fibers. Emerging evidence further points to sugar signaling as a 'hair-tonic' to boost fiber initiation through interaction with MBW complex and auxin signaling. An integrative model is provided as a conceptual framework for future studies to dissect the molecular network responsible for cotton fiber initiation.

Cell Wall Invertase and Sugar Transporters Are Differentially Activated in Tomato Styles and Ovaries During Pollination and Fertilization.

Flowering plants depend on pollination and fertilization to activate the transition from ovule to seed and ovary to fruit, namely seed and fruit set, which are key for completing the plant life cycle and realizing crop yield potential. These processes are highly energy consuming and rely on the efficient use of sucrose as the major nutrient and energy source. However, it remains elusive as how sucrose imported into and utilizated within the female reproductive organ is regulated in response to pollination and fertilization. Here, we explored this issue in tomato by focusing on genes encoding cell wall invertase (CWIN) and sugar transporters, which are major players in sucrose phloem unloading, and sink development. The transcript level of a major CWIN gene, LIN5, and CWIN activity were significantly increased in style at 4 h after pollination (HAP) in comparison with that in the non-pollination control, and this was sustained at 2 days after pollination (DAP). In the ovaries, however, CWIN activity and LIN5 expression did not increase until 2 DAP when fertilization occurred. Interestingly, a CWIN inhibitor gene INVINH1 was repressed in the pollinated style at 2 DAP. In response to pollination, the style exhibited increased expressions of genes encoding hexose transporters, SlHT1, 2, SlSWEET5b, and sucrose transporters SlSUT1, 2, and 4 from 4 HAP to 2 DAP. Upon fertilization, SlSUT1 and SlHT1 and 2, but not SlSWEETs, were also stimulated in fruitlets at 2 DAP. Together, the findings reveal that styles respond promptly and more broadly to pollination for activation of CWIN and sugar transporters to fuel pollen tube elongation, whereas the ovaries do not exhibit activation for some of these genes until fertilization occurs. HIGHLIGHTS: Expression of genes encoding cell wall invertases and sugar transporters was stimulated in pollinated style and fertilized ovaries in tomato.