A TILLING allele of the tomato Aux/IAA9 gene offers new insights into fruit set mechanisms and perspectives for breeding seedless tomatoes

Parthenocarpy is a desired trait in fruit crops; it enables fruit set under environmental conditions suboptimal for pollination, and seedless fruits represent a valuable consumer product. We employed TILLING-based screening of a mutant tomato population to find genetic lesions in Aux/IAA9, a negative regulator of the auxin response involved in the control of fruit set. We identified three mutations located in the coding region of this gene, including two singlebase substitutions and one single-base deletion, which leads to a frame shift and premature stop codon. The transcription of IAA9 was strongly reduced in the frame-shift mutant, and partial loss of mutated protein activity was evidenced by an in vitro transactivation assay. Whereas missense mutations were predicted to be tolerated and did not cause mutant phenotypes, the frame-shift mutation-induced phenotypes expected for a loss of IAA9 function, including altered axillary shoot growth, reduced leaf compoundness and a strong tendency to produce parthenocarpic fruits. Mutant flowers showed pleiotropic anther cone defects, a phenotype frequently associated with parthenocarpy in tomato and other species. Mutant fruits were larger than those of the seeded control, with higher bri

Are leaf chlorophyll fluorescence and Dark Green stressor-specific fingerprints in grapevine under drought or salt stress? A reanalysis study

Early and accurate recognition of abiotic stress types is essential for accelerating the selection of stress-tolerant varieties and implementing effective management strategies. This study is motivated by the socio-economic relevance of vineyard and by the increasing need for stressor-specific fingerprint(s) to support the reliable identification of stress type (e.g., drought or salinity) within a high-throughput plant phenotyping domain. This paper presents a reanalysis of physiological and phenotyping data from drought and salt stress experiments in Vitis vinifera focussing the maximum photosynthetic efficiency (Fv/Fm) and leaf Dark Green color. The reanalysis suggests that salt-stressed vines might suffer additional (non-stomatal) limitations curbing net photosynthetic rate (Pn) severely as drought stress does at equivalent stomatal conductance (gs) levels. Through a Principal Component (PC) Analysis, physiological and colorimetric response variables were decomposed revealing that Fv/Fm and Dark Green dominates the non-stomatal PC (∼80 %) clustering data between salt and drought experiments. Confusion matrices reveal that model based on Fv/Fm and Dark Green performed better (accuracy = 1, precision =1) than that based on Pn, gs, transpiration, and stem water potential. This study supports the potential use of Fv/Fm and Dark Green for early and non-destructive stress type identification

Physiological and image-based phenotyping assessment of waterlogging responses of three kiwifruit rootstocks and grafting combinations

Introduction: Kiwifruit species have a relatively high rate of root oxygen consumption, making them very vulnerable to low root zone oxygen concentrations resulting from soil waterlogging. Recently, kiwifruit rootstocks have been increasingly used to improve biotic and abiotic stress tolerance and crop performance under adverse conditions. The aim of the present study was to evaluate morpho-physiological changes in kiwifruit rootstocks and grafting combinations under short-term waterlogging stress. Methods: A pot trial was conducted at the ALSIA PhenoLab, part of the Phen-Italy infrastructures, using non-destructive RGB and NIR image-based analysis and physiological measurements to identify waterlogging stress indicators and more tolerant genotypes. Three pot-grown kiwifruit rootstocks (‘Bounty 71,’ Actinidia macrosperma—B; ‘D1,’ Actinidia chinensis var. deliciosa—D; and ‘Hayward,’ A. chinensis var. deliciosa—H) and grafting combinations, with a yellow-fleshed kiwifruit cultivar (‘Zesy 002,’ A. chinensis var. chinensis) grafted on each rootstock (Z/B, Z/D, Z/H), were subjected to a control irrigation treatment (WW), restoring their daily water consumption, and to a 9-day waterlogging stress (WL), based on substrate saturation. Leaf gas exchange, photosynthetic activity, leaf temperature, RGB, and NIR data were collected during waterlogging stress. Results: Stomatal conductance and transpiration reached very low values (less than 0.05 mol m−2 s−1 and 1 mmol m−2 s−1, respectively) in both waterlogged D and H rootstocks and their grafting combinations. In turn, leaf temperature was significantly increased and photosynthesis was reduced (1–6 μmol m−2 s−1) from the first days of waterlogging stress compared to B rootstock and combination. Discussion: The B rootstock showed prolonged leaf gas exchange and photosynthetic activity, indicating that it can cope with short-term and temporary waterlogging and improve the tolerance of grafted kiwi vines, which showed a decrease in stomatal conductance 5 days after the onset of stress. Morphometric and colorimetric parameters from the image-based analysis confirmed the greater susceptibility of D and H rootstocks and their grafting combinations to waterlogging stress compared to B. The results presented confirm the role of physiological measurements and enhance that of RGB and NIR images in detecting the occurrence of water stress and identifying more tolerant genotypes in kiwifruit

Innovation in grapevine water status monitoring and drought adaptation: leaf angle and temperature regulation

Increase of frequency, duration, and intensity of drought and heatwave and related water and heat crops stress are among the principal effects of climate change. This paper reports: (i) the effect of calcite particle film (CaPF) as a mitigation strategy against heat stress in well-watered (WW) or in drought-stress (D) conditions; and (ii) response of leaf angle variation to stomatal conductance changes induced by drought stress of Aleatico grapevine cultivar. Results have showed that CaPF, under WW conditions, reduced leaf temperature, and increased gas exchange, but, under very severe water stress, CaPF treatment was ineffective. Leaf angle ranged from 70° (WW vines) to 100° (drought stressed vines) and showed a good fit (R2 =0.81) with stomatal conductance within the range of 0.25 – 0.05 mol m-2 s–1 proving it might be a reliable proxy of vine water status

Preliminary high-throughput phenotyping analysis in grapevines under drought

This study reports correlative information between leaf water potential (ψ), total leaf area of draughted grapevines (Vitis vinifera L.) and non-destructive image analysis techniques. Four groups of 20 potted vines each were subjected to various irrigation treatments restoring 100% (control), 75%, 50% and 25% of daily water consumption within a 22-day period of drought imposition. Leaf gas exchanges (Li-Cor 6400), ψ (Scholander chamber), fluorescence (PAM − 2500), RGB and NIR (Scanalyzer 3D system, LemnaTec GmbH phenotyping platform) data were collected before and at the end of drought imposition. Values of ψ in severely stressed vines (25%) reached −1.2 MPa pre-dawn, in turn stomatal conductance and photosynthesis reached values as low as approx. 0.02 mol H2O m−2 s−1 and 1.0 μmol CO2 m−2 s−1, respectively. The high-throughput analysis preliminarily revealed a correlation between ψ (stem) and NIR Color Class (R2=0.80), and that plant leaf area might be accurately estimated through imagine analysis (R2=0.90)

Towards In Vivo Monitoring of Ions Accumulation in Trees: Response of an in Planta Organic Electrochemical Transistor Based Sensor to Water Flux Density, Light and Vapor Pressure Deficit Variation

Research on organic electrochemical transistor (OECT) based sensors to monitor in vivo plant traits such as xylem sap concentration is attracting attention for their potential application in precision agriculture. Fabrication and electronic aspects of OECT have been the subject of extensive research while its characterization within the plant water relation context deserves further efforts. This study tested the hypothesis that the response (R) of an OECT (bioristor) implanted in the trunk of olive trees is inversely proportional to the water flux density flowing through the plant (Jw). This study also examined the influence on R of vapor pressure deficit (VPD) as coupled/uncoupled with light. R was hourly recorded in potted olive trees for a 10-day period concomitantly with Jw (weight loss method). A subgroup of trees was bagged in order to reduce VPD and in turn Jw, and other trees were located in a walk-in chamber where VPD and light were independently managed. R was tightly sensitive to diurnal oscillation of Jw and at negligible values of Jw (late afternoon and night) R increased. The bioristor was not sensitive to the VPD per se unless a light source was coupled to trigger Jw. This study preliminarily examined the suitability of bioristor to estimate the mean daily nutrients accumulation rate (Ca, K) in leaves comparing chemical and sensor-based procedures showing a good agreement between them opening new perspective towards the application of OECT sensor in precision agricultural cropping systems

A rare case of omental extra-gastrointestinal stromal tumor showing two coexisting mutations on exon 14 of the PDGFRA gene

Gastrointestinal stromal tumors (GISTs) are neoplasms arising from mesenchymal cells localized into the muscularis propria of the gastrointestinal (GI) tract [1]; 5% of GISTs are extra-GISTs (EGISTs), as they differently originate from adipose tissue adjacent to the GI tract (omentum and mesentery) or from the pancreas [2]. So far, both GISTs and EGISTs have been managed indistinctively by combining surgery, histopathological distinctive features, imaging, and molecular analysis. Moreover, despite the contribution of defined genetic backgrounds whose influence is acknowledged in this type of tumor (i.e. Carney’s triad or familiar form of GIST), the pathobiology of both GISTs and EGISTs is not yet fully understood. We describe an interesting case of an extensively diffuse EGIST involving only omentum and mesocolon with multinodular growth and peculiar histological features, and for which a deeper histopathological/ molecular analysis is reported. Case presentation A 74-year-old female with a historical diagnosis of multiple myeloma was referred for anemia, alvus disorders (diarrhea and constipation), weight loss (15 kg in 6 months), and palpable mass of the right flank that had appeared 8 weeks before. On medication for multiple myeloma since 2016 (melphalan combined with prednisone and bortezomib9; carfilzomib/lenalidomide/ desametasone6 until complete remission), she also had type II diabetes, treated with oral medications and open cholecystectomy in the 1980s. Physical examination revealed the presence of a large mobile non-painful mass in the right flank apparently from the right colon, without signs of occlusion or intestinal bleeding. Blood analysis showed: hemoglobin 7.9 g/dL, white blood cells 2.3103/lL, glycemia 191 mg/dL, and a low potassium level of 2.8 mEq/L. We first treated the glycemia by insulin infusion and, second, we investigated the signs of anemia. By lower GI Submitted: 14 May 2020; Revised: 20 July 2020; Accepted: 28 July 202

Image-based sensing of salt stress in grapevine

Grapevine is among the most economically important crops suffering environmental constraints, including drought and salt stress. Although imaging is increasingly used to detect abiotic stress in agriculture, image-based phenotyping in grapevine still needs optimisation. This study presents the RGB-(red, green, blue)-based phenotyping of the early stage of salt stress response in potted grapevine (Aleatico/SO4) irrigated with saline water (100 mM NaCl) for 9 days in contrast with vines irrigated with fresh water. The response was measured using stomatal conductance (gs), net photosynthetic rate (A), transpiration (E), maximum potential photosynthetic efficiency (Fv/Fm), stem water potential (SWP) concurrently with RGB imaging via a robotised platform. The image-based phenotyping of salt-stressed vines employed two sets of measurements: (i) the pixel fraction of specific colour bands (Yellow, Green, Brown and Dark Green) and (ii) the mean pixel value of R, G and B and other RGB-based colorimetric indexes. Results show that the responses of gs, A, E, Fv/Fm were closely related to increasing soil electrical conductivity (EC) and that imaging could detect the EC threshold of approx. 4 dS m-1 causing a ~60 % decrease in these physiological traits compared to the pre-stress level. The SWP declined to about –0.7 MPa at the end of the experiment. The change of the relative pixel fraction of Dark Green to increasing EC has been analysed within a dose-response context, showing that a decrease of 1 % of the Dark Green colour band corresponded to the 4 dS m-1 EC threshold. This study also examined the use of the mean pixel value of the R, G and B channels as proxies of EC along with new RGB-based indexes resulting from the rearrangement of original R, G and B mean pixel values. Results show the suitability of the mean pixel value of R and Coloration Index [(R-B)/R] to serve as predictors of EC (R2 >= 0.80)