Mining key genes associated with phosphorus deficiency through genome-wide identification and characterization of cucumber SPX family genes.

BACKGROUND: Proteins harboring the SPX domain are crucial for the regulation of phosphate (Pi) homeostasis in plants. This study aimed to identify and analyze the entire SPX gene family within the cucumber genome. RESULTS: The cucumber genome encompassed 16 SPX domain-containing genes, which were distributed across six chromosomes and categorized into four distinct subfamilies: SPX, SPX-MFS, SPX-EXS and SPX-RING, based on their structure characteristics. Additionally, gene duplications and synteny analysis were conducted for CsSPXs, revealing that their promoter regions were enriched with a variety of hormone-responsive, biotic/abiotic stress and typical P1BS-related elements. Tissue expression profiling of CsSPX genes revealed that certain members were specifically expressed in particular organs, suggesting essential roles in cucumber growth and development. Under low Pi stress, CsSPX1 and CsSPX2 exhibited a particularly strong response to Pi starvation. It was observed that the cucumber cultivar Xintaimici displayed greater tolerance to low Pi compared to black-spined cucumber under low Pi stress conditions. Protein interaction networks for the 16 CsSPX proteins were predicted, and yeast two-hybrid assay revealed that CsPHR1 interacted with CsSPX2, CsSPX3, CsSPX4 and CsSPX5, implying their involvement in the Pi signaling pathway in conjunction with CsPHR1. CONCLUSION: This research lays the foundation for further exploration of the function of the CsSPX genes in response to low Pi stress and for elucidating the underlying mechanism.

Inferring Population HIV Viral Load From a Single HIV Clinic's Electronic Health Record: Simulation Study With a Real-World Example.

BACKGROUND: Population viral load (VL), the most comprehensive measure of the HIV transmission potential, cannot be directly measured due to lack of complete sampling of all people with HIV. OBJECTIVE: A given HIV clinic's electronic health record (EHR), a biased sample of this population, may be used to attempt to impute this measure. METHODS: We simulated a population of 10,000 individuals with VL calibrated to surveillance data with a geometric mean of 4449 copies/mL. We sampled 3 hypothetical EHRs from (A) the source population, (B) those diagnosed, and (C) those retained in care. Our analysis imputed population VL from each EHR using sampling weights followed by Bayesian adjustment. These methods were then tested using EHR data from an HIV clinic in Delaware. RESULTS: Following weighting, the estimates moved in the direction of the population value with correspondingly wider 95% intervals as follows: clinic A: 4364 (95% interval 1963-11,132) copies/mL; clinic B: 4420 (95% interval 1913-10,199) copies/mL; and clinic C: 242 (95% interval 113-563) copies/mL. Bayesian-adjusted weighting further improved the estimate. CONCLUSIONS: These findings suggest that methodological adjustments are ineffective for estimating population VL from a single clinic's EHR without the resource-intensive elucidation of an informative prior.

Development of Recommendations for the Digital Sharing of Notes With Adolescents in Mental Health Care: Delphi Study.

Background: In many countries, health care professionals are legally obliged to share information from electronic health records with patients. However, concerns have been raised regarding the sharing of notes with adolescents in mental health care, and health care professionals have called for recommendations to guide this practice. Objective: The aim was to reach a consensus among authors of scientific papers on recommendations for health care professionals' digital sharing of notes with adolescents in mental health care and to investigate whether staff at child and adolescent specialist mental health care clinics agreed with the recommendations. Methods: A Delphi study was conducted with authors of scientific papers to reach a consensus on recommendations. The process of making the recommendations involved three steps. First, scientific papers meeting the eligibility criteria were identified through a PubMed search where the references were screened. Second, the results from the included papers were coded and transformed into recommendations in an iterative process. Third, the authors of the included papers were asked to provide feedback and consider their agreement with each of the suggested recommendations in two rounds. After the Delphi process, a cross-sectional study was conducted among staff at specialist child and adolescent mental health care clinics to assess whether they agreed with the recommendations that reached a consensus. Results: Of the 84 invited authors, 27 responded. A consensus was reached on 17 recommendations on areas related to digital sharing of notes with adolescents in mental health care. The recommendations considered how to introduce digital access to notes, write notes, and support health care professionals, and when to withhold notes. Of the 41 staff members at child and adolescent specialist mental health care clinics, 60% or more agreed with the 17 recommendations. No consensus was reached regarding the age at which adolescents should receive digital access to their notes and the timing of digitally sharing notes with parents. Conclusions: A total of 17 recommendations related to key aspects of health care professionals' digital sharing of notes with adolescents in mental health care achieved consensus. Health care professionals can use these recommendations to guide their practice of sharing notes with adolescents in mental health care. However, the effects and experiences of following these recommendations should be tested in clinical practice.

Comparative functional analyses of PHR1, PHL1, and PHL4 transcription factors in regulating Arabidopsis responses to phosphate starvation.

To cope with phosphate (Pi) starvation, plants trigger an array of adaptive responses to sustain their growth and development. These responses are largely controlled at transcriptional levels. In Arabidopsis (Arabidopsis thaliana), PHOSPHATE RESPONSE 1 (PHR1) is a key regulator of plant physiological and transcriptional responses to Pi starvation. PHR1 belongs to a MYB-CC-type transcription factor family which contains 15 members. In this PHR1 family, PHR1/PHR1-like 1(PHL1) and PHL2/PHL3 form two distinct modules in regulating plant development and transcriptional responses to Pi starvation. PHL4 is the most closely related member to PHR1. Previously, using the phr1phl4 mutant, we showed that PHL4 is also involved in regulating plant Pi responses. However, the precise roles of PHL1 and PHL4 in regulating plant Pi responses and their functional relationships with PHR1 have not been clearly defined. In this work, we further used the phl1phl4 and phr1phl1phl4 mutants to perform comparative phenotypic and transcriptomic analyses with phr1, phr1phl1, and phr1phl4. The results showed that both PHL1 and PHL4 act redundantly and equally with PHR1 to regulate leaf senescence, Pi starvation induced-inhibition of primary root growth, and accumulation of anthocyanins in shoots. Unlike PHR1 and PHL1, however, the role of PHL4 in maintaining Pi homeostasis is negligible. In regulating transcriptional responses to Pi starvation at genomic levels, both PHL1 and PHL4 play minor roles when acts alone, however, they act synergistically with PHR1. In regulating Pi starvation-responsive genes, PHL4 also function less than PHL1 in terms of the number of the genes it regulates and the magnitude of gene transcription it affects. Furthermore, no synergistic interaction was found between PHL1 and PHL4 in regulating plant response to Pi starvation. Therefore, our results clarified the roles of PHL1 and PHL4 in regulating plant responses to Pi starvation. In addition, this work revealed a new function of these three transcription factors in regulating flowering time.

OsMYB58 Negatively Regulates Plant Growth and Development by Regulating Phosphate Homeostasis.

Phosphate (Pi) starvation is a critical factor limiting crop growth, development, and productivity. Rice (Oryza sativa) R2R3-MYB transcription factors function in the transcriptional regulation of plant responses to various abiotic stresses and micronutrient deprivation, but little is known about their roles in Pi starvation signaling and Pi homeostasis. Here, we identified the R2R3-MYB transcription factor gene OsMYB58, which shares high sequence similarity with AtMYB58. OsMYB58 expression was induced more strongly by Pi starvation than by other micronutrient deficiencies. Overexpressing OsMYB58 in Arabidopsis thaliana and rice inhibited plant growth and development under Pi-deficient conditions. In addition, the overexpression of OsMYB58 in plants exposed to Pi deficiency strongly affected root development, including seminal root, lateral root, and root hair formation. Overexpressing OsMYB58 strongly decreased the expression of the rice microRNAs OsmiR399a and OsmiR399j. By contrast, overexpressing OsMYB58 strongly increased the expression of rice PHOSPHATE 2 (OsPHO2), whose expression is repressed by miR399 during Pi starvation signaling. OsMYB58 functions as a transcriptional repressor of the expression of its target genes, as determined by a transcriptional activity assay. These results demonstrate that OsMYB58 negatively regulates OsmiR399-dependent Pi starvation signaling by enhancing OsmiR399s expression.

WRKY33 negatively regulates anthocyanin biosynthesis and cooperates with PHR1 to mediate acclimation to phosphate starvation.

Anthocyanin accumulation is acknowledged as a phenotypic indicator of phosphate (Pi) starvation. However, negative regulators of this process and their molecular mechanisms remain largely unexplored. In this study, we demonstrate that WRKY33 acts as a negative regulator of phosphorus-status-dependent anthocyanin biosynthesis. WRKY33 regulates the expression of the gene encoding dihydroflavonol 4-reductase (DFR), a rate-limiting enzyme in anthocyanin production, both directly and indirectly. WRKY33 binds directly to the DFR promoter to repress its expression and also interferes with the MBW complex through interacting with PAP1 to indirectly influence DFR transcriptional activation. Under -Pi conditions, PHR1 interacts with WRKY33, and the protein level of WRKY33 decreases; the repression of DFR expression by WRKY33 is thus attenuated, leading to anthocyanin accumulation in Arabidopsis. Further genetic and biochemical assays suggest that PHR1 is also involved in regulating factors that affect WRKY33 protein turnover. Taken together, our findings reveal that Pi starvation represses WRKY33, a repressor of anthocyanin biosynthesis, to finely tune anthocyanin biosynthesis. This "double-negative logic" regulation of phosphorus-status-dependent anthocyanin biosynthesis is required for the maintenance of plant metabolic homeostasis during acclimation to Pi starvation.

Transcriptional expression of PHR2 is positively controlled by the calcium signaling transcription factor Crz1 through its binding motif in the promoter.

IMPORTANCE: The fungal cell wall consists of glucans, mannoproteins, and chitin and is essential for cell viability, morphogenesis, and pathogenesis. The enzymes of the GH72 family are responsible for ß-(1,3)-glucan elongation and branching, which is crucial for the formation of the glucan-chitin polymer at the bud neck of yeast cells. In the human fungal pathogen Candida albicans, there are five GH72 enzyme-encoding genes: PHR1, PHR2, PHR3, PGA4, and PGA5. It is known that expression of PHR1 and PHR2 is controlled by the pH-responsive Rim101 pathway through the transcription factor Rim101. In this study, we have demonstrated that the transcription expression of PHR2 is also controlled by the transcription factor Crz1 through its binding motif in the promoter. Therefore, we have uncovered a dual-control mechanism by which PHR2 expression is negatively regulated via CaRim101 through the pH-responsive pathway and positively modulated by CaCrz1 through the calcium/calcineurin signaling pathway.

Unraveling the potential of the strigolactones-NSP1/NSP2 friendship in crop improvement.

Strigolactones (SLs) are fundamental to the ability of plants to cope with phosphate deficiency. A recent study by Yuan et al. indicates that the genetic module PHR2/NSP1/NSP2 is crucial in activating SL biosynthesis and signaling under inorganic phosphate (Pi) deficiency. Furthermore, this genetic module is essential for improving Pi and nitrogen homeostasis in rice.

Usability and Perception of a Wearable-Integrated Digital Maternity Record App in Germany: User Study.

Background: Although digital maternity records (DMRs) have been evaluated in the past, no previous work investigated usability or acceptance through an observational usability study. Objective: The primary objective was to assess the usability and perception of a DMR smartphone app for pregnant women. The secondary objective was to assess personal preferences and habits related to online information searching, wearable data presentation and interpretation, at-home examination, and sharing data for research purposes during pregnancy. Methods: A DMR smartphone app was developed. Key features such as wearable device integration, study functionalities (eg, questionnaires), and common pregnancy app functionalities (eg, mood tracker) were included. Women who had previously given birth were invited to participate. Participants completed 10 tasks while asked to think aloud. Sessions were conducted via Zoom. Video, audio, and the shared screen were recorded for analysis. Task completion times, task success, errors, and self-reported (free text) feedback were evaluated. Usability was measured through the System Usability Scale (SUS) and User Experience Questionnaire (UEQ). Semistructured interviews were conducted to explore the secondary objective. Results: A total of 11 participants (mean age 34.6, SD 2.2 years) were included in the study. A mean SUS score of 79.09 (SD 18.38) was achieved. The app was rated "above average" in 4 of 6 UEQ categories. Sixteen unique features were requested. We found that 5 of 11 participants would only use wearables during pregnancy if requested to by their physician, while 10 of 11 stated they would share their data for research purposes. Conclusions: Pregnant women rely on their medical caregivers for advice, including on the use of mobile and ubiquitous health technology. Clear benefits must be communicated if issuing wearable devices to pregnant women. Participants that experienced pregnancy complications in the past were overall more open toward the use of wearable devices in pregnancy. Pregnant women have different opinions regarding access to, interpretation of, and reactions to alerts based on wearable data. Future work should investigate personalized concepts covering these aspects.

A glycosylated Phr1 protein is induced by calcium stress and its expression is positively controlled by the calcium/calcineurin signaling transcription factor Crz1 in Candida albicans.

As one of the most important human fungal pathogens, Candida albicans senses and adapts to host niches with different pH values through the pH-responsive Rim101 pathway. Its transcription factor Rim101 activates the expression of alkaline pH-induced genes including PHR1 that encodes a glycosylphosphatidylinsitol-anchored ß(1,3)-glucanosyltransferase critical for hyphal wall formation. The calcium/calcineurin signaling pathway is mediated by the transcription factor Crz1 in yeasts and other lower eukaryotes. Here we report that deletion of PHR1 leads to calcium sensitivity of C. albicans cells. In addition, expression of Phr1 is induced by calcium stress and under the control of Crz1 in C. albicans. EMSA assay demonstrates that Crz1 binds to one CDRE element in the PHR1 promoter. Alkaline treatment induces two species of glycosylated Phr1 proteins with different degrees of glycosylation, which is independent of Crz1. In contrast, only one species of Phr1 protein with a low degree of glycosylation is induced by calcium stress in a Crz1-dependent fashion. Therefore, we have provided an evidence that regulation of cell wall remodeling is integrated through differential degrees of Phr1 glycosylation by both the pH-regulated Rim101 pathway and the calcium/calcineurin signaling pathway in C. albicans. Video Abstract.

Personal Health Record (PHR) Experience and Recommendations for a Transformation in Saudi Arabia.

A Personal Health Record (PHR) is a patient-managed platform for health data. Most hospitals provide a PHR as an extension of the Electronic Medical Record (EMR). However, there are unresolved issues around the adoption rate, functionalities, barriers and, more importantly, the impact of the PHR on patients' health. A cross-sectional, survey-based descriptive study was conducted in which patients from four main tertiary hospitals in Saudi Arabia were targeted from September 2022 to February 2023. The survey was tested and validated to address the objectives of the study. The survey covered components related to intention to use the PHR, required functions, obstacles and expected outcomes. This study involved 396 participants from the top four hospitals. It was discovered that the majority of them had intentions to use the PHR (93%) and believed it to be useful (94%) and easy to use (94%). It was widely agreed that accessing medical records (77%), scheduling appointments (88%), renewing medication (90%), tracking patient data (70%) and receiving personalized education (78%) were essential aspects of the PHR. Furthermore, the survey revealed that 54% of respondents saw a positive effect on their health status. A significant number of participants, around 54%, expressed concerns about the privacy of their PHR, and 46% reported concerns about the accuracy of their information. The study found that demographic factors and the type of hospital did not have a statistically significant association with the intention to use the PHR. Our findings showed that there were no significant barriers to adopting the PHR. Additionally, we found that less than half of the participants believed that their current PHR helped them to improve their health. This highlights the need for healthcare organizations to focus on improving the PHR's functionality and overall purpose. Instead of simply providing basic features, the PHR should allow patients to manage their health information comprehensively, including compiling information from hospitals and patient-generated data. Having a PHR is crucial in improving an individual's overall health. As technology advances, more data are being generated that should be included in the PHR to ensure an accurate and comprehensive view of the patient's health. Expanding the scope of the PHR to include capabilities beyond merely hospital data is important. Achieving this requires an open and honest discussion about the role of the PHR, potential obstacles and how to coordinate efforts among different stakeholders.

Role of SiPHR1 in the Response to Low Phosphate in Foxtail Millet via Comparative Transcriptomic and Co-Expression Network Analyses.

Enhancing the absorption and utilization of phosphorus by crops is an important aim for ensuring food security worldwide. However, the gene regulatory network underlying phosphorus use in foxtail millet remains unclear. In this study, the molecular mechanism underlying low-phosphorus (LP) responsiveness in foxtail millet was evaluated using a comparative transcriptome analysis. LP reduced the chlorophyll content in shoots, increased the anthocyanin content in roots, and up-regulated purple acid phosphatase and phytase activities as well as antioxidant systems (CAT, POD, and SOD). Finally, 13 differentially expressed genes related to LP response were identified and verified using transcriptomic data and qRT-PCR. Two gene co-expression network modules related to phosphorus responsiveness were positively correlated with POD, CAT, and PAPs. Of these, SiPHR1, functionally annotated as PHOSPHATE STARVATION RESPONSE 1, was identified as an MYB transcription factor related to phosphate responsiveness. SiPHR1 overexpression in Arabidopsis significantly modified the root architecture. LP stress caused cellular, physiological, and phenotypic changes in seedlings. SiPHR1 functioned as a positive regulator by activating downstream genes related to LP tolerance. These results improve our understanding of the molecular mechanism underlying responsiveness to LP stress, thereby laying a theoretical foundation for the genetic modification and breeding of new LP-tolerant foxtail millet varieties.

Optogenetic dissection of RET signaling reveals robust activation of ERK and enhanced filopodia-like protrusions of regenerating axons.

RET (REarranged during Transfection) is a receptor tyrosine kinase that transduces various external stimuli into biological functions, such as survival and differentiation, in neurons. In the current study, we developed an optogenetic tool for modulating RET signaling, termed optoRET, combining the cytosolic region of human RET with a blue-light-inducible homo-oligomerizing protein. By varying the duration of photoactivation, we were able to dynamically modulate RET signaling. Activation of optoRET recruited Grb2 (growth factor receptor-bound protein 2) and stimulated AKT and ERK (extracellular signal-regulated kinase) in cultured neurons, evoking robust and efficient ERK activation. By locally activating the distal part of the neuron, we were able to retrogradely transduce the AKT and ERK signal to the soma and trigger formation of filopodia-like F-actin structures at stimulated regions through Cdc42 (cell division control 42) activation. Importantly, we successfully modulated RET signaling in dopaminergic neurons of the substantia nigra in the mouse brain. Collectively, optoRET has the potential to be developed as a future therapeutic intervention, modulating RET downstream signaling with light.

Integrated personal health record (PHR) security: requirements and mechanisms.

BACKGROUND: Personal Health Records (PHRs) are designed to fulfill the goals of electronic health (eHealth) and empower the individual in the process of self-care. Integrated PHR can improve the quality of care, strengthen the patient-healthcare provider relationship, and reduce healthcare costs. Still, the process of PHR acceptance and use has been slow and mainly hindered by people's concerns about the security of their personal health information. Thus, the present study aimed to identify the Integrated PHR security requirements and mechanisms. METHODS: In this applied study, PHR security requirements were identified with a literature review of (library sources, research articles, scientific documents, and reliable websites). The identified requirements were classified, and a questionnaire was developed accordingly. Thirty experts completed the questionnaire in a two-round Delphi technique, and the data were analyzed by descriptive statistics. RESULTS: The PHR security requirements were identified and classified into seven dimensions confidentiality, availability, integrity, authentication, authorization, non-repudiation, and right of access, each dimension having certain mechanisms. On average, the experts reached an agreement about the mechanisms of confidentiality (94.67%), availability (96.67%), integrity (93.33%), authentication (100%), authorization (97.78%), non-repudiation (100%), and right of access (90%). CONCLUSION: Integrated PHR security is a requirement for its acceptance and use. To design a useful and reliable integrated PHR, system designers, health policymakers, and healthcare organizations must identify and apply security requirements to guarantee the privacy and confidentiality of data.

The E3 ubiquitin ligase SINA1 and the protein kinase BIN2 cooperatively regulate PHR1 in apple anthocyanin biosynthesis.

PHR1 (PHOSPHATE STARVATION RESPONSE1) plays key roles in the inorganic phosphate (Pi) starvation response and in Pi deficiency-induced anthocyanin biosynthesis in plants. However, the post-translational regulation of PHR1 is unclear, and the molecular basis of PHR1-mediated anthocyanin biosynthesis remains elusive. In this study, we determined that MdPHR1 was essential for Pi deficiency-induced anthocyanin accumulation in apple (Malus × domestica). MdPHR1 interacted with MdWRKY75, a positive regulator of anthocyanin biosynthesis, to enhance the MdWRKY75-activated transcription of MdMYB1, leading to anthocyanin accumulation. In addition, the E3 ubiquitin ligase SEVEN IN ABSENTIA1 (MdSINA1) negatively regulated MdPHR1-promoted anthocyanin biosynthesis via the ubiquitination-mediated degradation of MdPHR1. Moreover, the protein kinase apple BRASSINOSTEROID INSENSITIVE2 (MdBIN2) phosphorylated MdPHR1 and positively regulated MdPHR1-mediated anthocyanin accumulation by attenuating the MdSINA1-mediated ubiquitination degradation of MdPHR1. Taken together, these findings not only demonstrate the regulatory role of MdPHR1 in Pi starvation induced anthocyanin accumulation, but also provide an insight into the post-translational regulation of PHR1.

SlPHL1 is involved in low phosphate stress promoting anthocyanin biosynthesis by directly upregulation of genes SlF3H, SlF3'H, and SlLDOX in tomato.

Phosphate (Pi) deficiency is a common stress that limits plant growth and development. Plants exhibit a variety of Pi starvation responses (PSRs), including anthocyanin accumulation. The transcription factors of the PHOSPHATE STARVATION RESPONSE (PHR) family, such as AtPHR1 in Arabidopsis, play central roles in the regulation of Pi starvation signaling. Solanum lycopersicum PHR1-like 1 (SlPHL1) is a recently identified PHR involved in PSR regulation in tomato, but the detailed mechanism of its participation in Pi starvation-inducing anthocyanin accumulation remains unclear. Here we found that overexpression of SlPHL1 in tomato increases the expression of genes associated with anthocyanin biosynthesis, thereby promoting anthocyanin biosynthesis, but silencing SlPHL1 with Virus Induced Gene Silencing (VIGS) attenuated low phosphate (LP) stress-induced anthocyanin accumulation and expression of the biosynthesis-related genes. Notably, SlPHL1 is able to bind the promoters of genes Flavanone 3-Hydroxylase (SlF3H), Flavanone 3'-Hydroxylase (SlF3'H), and Leucoanthocyanidin Dioxygenase (SlLDOX) by yeast one-hybrid (Y1H) analysis. Furthermore, Electrophoretic Mobility Shift Assay (EMSA) and transient transcript expression assay showed that PHR1 binding t (sequence (P1BS) motifs located on the promoters of these three genes are critical for SlPHL1 binding and enhancing the gene transcription. Additionally, allogenic overexpression of SlPHL1 could promote anthocyanin biosynthesis in Arabidopsis under LP conditions through the similar mechanism to AtPHR1, suggesting that SlPHL1 might be functionally conserved with AtPHR1 in this process. Taken together, SlPHL1 positively regulates LP-induced anthocyanin accumulation by directly promoting the transcription of SlF3H, SlF3'H and SlLDOX. These findings will contribute to understanding the molecular mechanism of PSR in tomato.

Silencing of SlSPX1 and SlSPX2 promote growth and root mycorrhization in tomato (Solanum lycopersicum L.) seedlings.

Owing to the essential requirement of phosphorus (P) for growth and development, plants tightly control inorganic phosphate (Pi) homeostasis. SPX-PHR regulatory circuit not only control phosphate homeostasis responses but also root mycorrhization by arbuscular mycorrhiza (AM) fungi. Besides sensing Pi deficiency, SPX (SYG1/Pho81/XPR1) proteins also control the transcription of P starvation inducible (PSI) genes by blocking the activity of PHR1 (PHOSPHATE STARVATION RESPONSE1) homologs in plants under Pi-sufficient conditions. However, the roles of SPX members in Pi homeostasis and AM fungi colonization remain to be fully recognized in tomato. In this study, we identified 17 SPX-domain containing members in the tomato genome. Transcript profiling revealed the high Pi-specific nature of their activation. Four SlSPX members have also induced in AM colonized roots. Interestingly, we found that SlSPX1 and SlSPX2 are induced by P starvation and AM fungi colonization. Further, SlSPX1 and SlSPX2 exhibited varying degrees of interaction with the PHR homologs in this study. Virus-induced gene silencing-based (VIGS) transcript inhibition of these genes alone or together promoted the accumulation of higher total soluble Pi in tomato seedlings and improved their growth. It also enhanced AM fungi colonization in the roots of SlSPX1 and SlSPX2 silenced seedlings. Overall, the present study provides evidence in support of SlSPX members being good candidates for improving AM fungi colonization potential in tomato.

Cracking the code of plant central phosphate signaling.

Phosphate (Pi) is involved in numerous metabolic processes and plays a vital role in plant growth. Green plants have evolved intricate molecular bases of Pi signaling to maintain cellular Pi homeostasis. Here, we summarize recent advances in the molecular and structural bases of central Pi signaling and discuss pending questions.

Elucidating the unknown transcriptional responses and PHR1-mediated biotic and abiotic stress tolerance during phosphorus limitation.

Phosphorus (P) limitation in the majority of world soils is a major constraint for plant growth and crop productivity. RNA sequencing was used to discover novel P-responsive gene transcripts (PRGTs) in leaves and roots of Arabidopsis. Hisat StringTie and the Cufflinks TopHat transcript assembler were used to analyze reads and identify 1074 PRGTs with a >5-fold altered abundance during P limitation. Interestingly, 60% of these transcripts were not previously reported. Among the novel PRGTs, 106 were from unannotated genes, and some were among the most P-responsive, including At2g36727 which encodes a novel miRNA. Annotated novel PRGTs encode transcription factors, miRNAs, small signaling peptides, long non-coding RNAs, defense-related proteins, and transporters, along with proteins involved in many biological processes. We identified several genes that undergo alternative splicing during P limitation, including a novel miR399-resistant splice variant of PHOSPHATE2 (PHO2.2). Several novel P-responsive genes were regulated by PHOSPHATE STARVATION RESPONSE1 (PHR1), PHR1-LIKE 1 (PHL1), and PHO2. We discovered that P-limited plants show increased resistance to pathogens and drought stress mediated by PHR1-PHL1. Identification of novel P-responsive transcripts and the discovery of the influence of P limitation on biotic and abiotic stress adds a significant component to our understanding of plant P signaling.