Phosphorylation Dynamics in a flg22-Induced, G Protein-Dependent Network Reveals the AtRGS1 Phosphatase.

The microbe-associated molecular pattern flg22 is recognized in a flagellin-sensitive 2-dependent manner in root tip cells. Here, we show a rapid and massive change in protein abundance and phosphorylation state of the Arabidopsis root cell proteome in WT and a mutant deficient in heterotrimeric G-protein-coupled signaling. flg22-induced changes fall on proteins comprising a subset of this proteome, the heterotrimeric G protein interactome, and on highly-populated hubs of the immunity network. Approximately 95% of the phosphorylation changes in the heterotrimeric G-protein interactome depend, at least partially, on a functional G protein complex. One member of this interactome is ATBα, a substrate-recognition subunit of a protein phosphatase 2A complex and an interactor to Arabidopsis thaliana Regulator of G Signaling 1 protein (AtRGS1), a flg22-phosphorylated, 7-transmembrane spanning modulator of the nucleotide-binding state of the core G-protein complex. A null mutation of ATBα strongly increases basal endocytosis of AtRGS1. AtRGS1 steady-state protein level is lower in the atbα mutant in a proteasome-dependent manner. We propose that phosphorylation-dependent endocytosis of AtRGS1 is part of the mechanism to degrade AtRGS1, thus sustaining activation of the heterotrimeric G protein complex required for the regulation of system dynamics in innate immunity. The PP2A(ATBα) complex is a critical regulator of this signaling pathway.

State-of-the-Art Molecular Plant Sciences in Brazil.

Brazil has a crucial role in global food security and biodiversity, boasting one of the largest agricultural areas and two globally vital biomes, the Amazon and the Atlantic Forest [...].

Cadmium-mediated toxicity in plant cells is associated with the DCD/NRP-mediated cell death response.

Cadmium (Cd2+ ) is highly harmful to plant growth. Although Cd2+ induces programmed cell death (PCD) in plant cells, Cd2+ stress in whole plants during later developmental stages and the mechanism underlying Cd2+ -mediated toxicity are poorly understood. Here, we showed that Cd2+ limits plant growth, causes intense redness in leaf vein, leaf yellowing, and chlorosis during the R1 reproductive stage of soybean (Glycine max). These symptoms were associated with Cd2+ -induced PCD, as Cd2+ -stressed soybean leaves displayed decreased number of nuclei, enhanced cell death, DNA damage, and caspase 1 activity compared to unstressed leaves. Accordingly, Cd2+ -induced NRPs, GmNAC81, GmNAC30 and VPE, the DCD/NRP-mediated cell death signalling components, which execute PCD via caspase 1-like VPE activity. Furthermore, overexpression of the positive regulator of this cell death signalling GmNAC81 enhanced sensitivity to Cd2+ stress and intensified the hallmarks of Cd2+ -mediated PCD. GmNAC81 overexpression enhanced Cd2+ -induced H2 O2 production, cell death, DNA damage, and caspase-1-like VPE expression. Conversely, BiP overexpression negatively regulated the NRPs/GmNACs/VPE signalling module, conferred tolerance to Cd2+ stress and reduced Cd2+ -mediated cell death. Collectively, our data indicate that Cd2+ induces PCD in plants via activation of the NRP/GmNAC/VPE regulatory circuit that links developmentally and stress-induced cell death.

Profiling single-cell chromatin accessibility in plants.

Coupling assay for transposase-accessible chromatin sequencing (ATAC-seq) with microfluidic separation and cellular barcoding has emerged as a powerful approach to investigate chromatin accessibility of individual cells. Here, we define a protocol for constructing single-cell ATAC-seq libraries from maize seedling nuclei and the preliminary computational steps for assessing data quality. This protocol can be readily adapted to other plant species or tissues with minor changes to reveal chromatin accessibility variation among individual cells. For complete details on the use and execution of this protocol, please refer to Marand et al. (2021).

Senescence-Associated Glycine max (Gm)NAC Genes: Integration of Natural and Stress-Induced Leaf Senescence.

Leaf senescence is a genetically regulated developmental process that can be triggered by a variety of internal and external signals, including hormones and environmental stimuli. Among the senescence-associated genes controlling leaf senescence, the transcriptional factors (TFs) comprise a functional class that is highly active at the onset and during the progression of leaf senescence. The plant-specific NAC (NAM, ATAF, and CUC) TFs are essential for controlling leaf senescence. Several members of Arabidopsis AtNAC-SAGs are well characterized as players in elucidated regulatory networks. However, only a few soybean members of this class display well-known functions; knowledge about their regulatory circuits is still rudimentary. Here, we describe the expression profile of soybean GmNAC-SAGs upregulated by natural senescence and their functional correlation with putative AtNAC-SAGs orthologs. The mechanisms and the regulatory gene networks underlying GmNAC081- and GmNAC030-positive regulation in leaf senescence are discussed. Furthermore, new insights into the role of GmNAC065 as a negative senescence regulator are presented, demonstrating extraordinary functional conservation with the Arabidopsis counterpart. Finally, we describe a regulatory circuit which integrates a stress-induced cell death program with developmental leaf senescence via the NRP-NAC-VPE signaling module.

Contrasting roles of GmNAC065 and GmNAC085 in natural senescence, plant development, multiple stresses and cell death responses.

NACs are plant-specific transcription factors involved in controlling plant development, stress responses, and senescence. As senescence-associated genes (SAGs), NACs integrate age- and stress-dependent pathways that converge to programmed cell death (PCD). In Arabidopsis, NAC-SAGs belong to well-characterized regulatory networks, poorly understood in soybean. Here, we interrogated the soybean genome and provided a comprehensive analysis of senescence-associated Glycine max (Gm) NACs. To functionally examine GmNAC-SAGs, we selected GmNAC065, a putative ortholog of Arabidopsis ANAC083/VNI2 SAG, and the cell death-promoting GmNAC085, an ANAC072 SAG putative ortholog, for analyses. Expression analysis of GmNAC065 and GmNAC085 in soybean demonstrated (i) these cell death-promoting GmNACs display contrasting expression changes during age- and stress-induced senescence; (ii) they are co-expressed with functionally different gene sets involved in stress and PCD, and (iii) are differentially induced by PCD inducers. Furthermore, we demonstrated GmNAC065 expression delays senescence in Arabidopsis, a phenotype associated with enhanced oxidative performance under multiple stresses, higher chlorophyll, carotenoid and sugar contents, and lower stress-induced PCD compared to wild-type. In contrast, GmNAC085 accelerated stress-induced senescence, causing enhanced chlorophyll loss, ROS accumulation and cell death, decreased antioxidative system expression and activity. Accordingly, GmNAC065 and GmNAC085 targeted functionally contrasting sets of downstream AtSAGs, further indicating that GmNAC85 and GmNAC065 regulators function inversely in developmental and environmental PCD.

Tonic pupil in leprosy / Pupila tônica em doença de Hansen

Pupil abnormalities in leprosy usually result from chronic iritis with loss of stroma, iris miosis, a sluggish reaction to light, and poor dilation in response to anticholinergic mydriatics. We report two patients with long-standing lepromatous leprosy who developed tonic pupils characterized by mydriasis, absence of reaction to light and hypersensitivity to weak cholinergic solution. Examination revealed iritis and iris atrophy. In both cases, instillation of dilute 0.1% pilocarpine caused miosis in the affected eyes. Tonic pupil occurs in many conditions, but its association with leprosy had not been previously reported.

Anormalidades da pupila em pacientes com doença de Hansen, ocorrem mais comumente devido a irite crônica com perda do estroma iriano, miose, diminuição da reação à luz, e dificuldade de dilatação em resposta a colírios anticolinérgicos. Relatamos dois pacientes com doença de Hansen na forma lepromatosa que desenvolveram pupilas tônicas, caracterizadas por midríase, ausência de reação a luz e para perto e hipersensibilidade a fraca concentração de solução colinérgica. O exame revelou irite e atrofia iriana. Em ambos os casos a instilação de pilocarpina 0,1% causou miose nos olhos afetados. A pupila tônica tem sido relatada em muitas condições, mas sua associação com doença de Hansen ainda não havia sido descrita.

Tonic pupil in leprosy.

Pupil abnormalities in leprosy usually result from chronic iritis with loss of stroma, iris miosis, a sluggish reaction to light, and poor dilation in response to anticholinergic mydriatics. We report two patients with long-standing lepromatous leprosy who developed tonic pupils characterized by mydriasis, absence of reaction to light and hypersensitivity to weak cholinergic solution. Examination revealed iritis and iris atrophy. In both cases, instillation of dilute 0.1% pilocarpine caused miosis in the affected eyes. Tonic pupil occurs in many conditions, but its association with leprosy had not been previously reported.

Silicone oil tamponade in 23-gauge transconjunctival sutureless vitrectomy.

PURPOSE: To describe 20 consecutive patients treated with 23-gauge transconjunctival sutureless vitrectomy and silicone oil tamponade for retinal detachments (RD) of different etiologies. METHODS: Prospective case series. Twenty patients with complex retinal detachment were submitted to a primary 23-gauge transconjunctival pars plana vitrectomy: rhegmatogenous retinal detachment with proliferative vitreoretinopathy (RRD + PVR) in 7 cases, diabetic tractional retinal detachment (DTRD) in 5 cases, giant retinal tear (GRT) in 2 cases, RRD with multiple tears in 2 cases, GRT + uveitis in 1 case, RRD + uveitis in 1 case, DTRD + RRD in 1 case, and RRD + PVR with intraocular foreign body (IOFB) in 1 case. Length of postoperative follow up ranged from 3 to 14 months. RESULTS: Final visual acuity ranged from 20/25 to hand motion. Postoperatively, none of the 20 eyes had hypotony or leakage of silicone oil through the sclerotomies. Seventeen out of 20 (85%) had improved vision. CONCLUSION: Silicone oil tamponade was demonstrated to be a feasible option in conjunction with 23-g transconjunctival sutureless vitrectomy to treat complex retinal detachment.

Photodynamic therapy-treated choroidal neovascular membrane secondary to toxoplasmic retinochoroiditis.

PURPOSE: To report the result of photodynamic therapy with Visudyne (PDT) on a child with choroidal neovascular membrane (CNV) secondary to toxoplasmic retinochoroiditis. METHODS: An 11-year-old child with a unilateral lowering of visual acuity secondary to an extrafoveal choroidal neovascular membrane was submitted to PDT. RESULTS: One week after PDT, the patient's vision had improved from 10/160 to 20/70, with marked improvement in the angiographic findings. The CNV evolved with decreasing of leakage until 45 days after operation, when it regressed to a chorioretinal scar formation, with final vision of 20/25. CONCLUSION: PDT promoted an early recovery of visual acuity in an eye with choroidal neovascularization secondary to toxoplasmic retinochoroiditis.

Características da populaçäo portadora de visäo subnormal do Hospital Säo Geraldo: um estudo retrospectivo de 435 casos / Low vision patients at Hospital Säo Geraldo: a revision of 435 cases

Foram analisados 435 prontuários do Serviço de Visäo Subnormal (VSN) do Hospital Säo Geraldo (HSG) - Hospital das Clínicas/UFMG - de 1992 a 1996, com o objetivo de conhecer as características da populaçäo portadora de VSN segundo a faixa etária do sexo, procedência, escolaridade, profissäo, etiologia, acuidade visual para longe, objetivo do paciente com os auxílios ópticos e a sua prescriçäo para longe e perto. As características encontradas säo analisadas e comparadas com outros achados da literatura. Os autores discutem a importância do conhecimento das características da populaçäo portadora de VSN com a finalidade de criar programas preventivos e melhores condiçöes de atendimento