3D root system architecture of woody plant can be assessed using structure from motion photogrammetry

We aim to propose a validated methodology to assess rapidly 3D root system architecture, getting axes and segments, using Structure from Motion in woody plants grown in the field. An accurate pipeline has been setup for SfM, giving similar results to manual measurements and 3D-digitizing

Tackling the 3D root system architecture of grapevines: a new phenotyping pipeline based on photogrammetry

Plant roots fulfil important functions as they are responsible for the acquisition of water and nutrients, for anchorage and stability, for interaction with symbionts and, in some cases, for the storage of carbohydrates. These functions are associated with the Root System Architecture (RSA, i.e. the form and the spatial arrangement of the roots in the soil). The RSA results from several biological processes (elongation, ramification, mortality…) genetically determined but with high structural plasticity. In grapevine, several factors can influence the RSA development (e.g. rootstock and scion genotypes, soil and plant management…). However, the effects of all these factors on the establishment of the RSA and associated functions (e.g. drought tolerance) have hardly ever been assessed. Such an assessment could help to improve the management of vineyards in our changing world. This lack of knowledge is mainly associated to methodological difficulties to characterize the RSA during grapevine development in the vineyard. To take up this challenge, we developed a new phenotyping pipeline, connecting photogrammetric data (produced by ArcheovisionProduction) with plant structures reconstruction software (PlantScan3D) and two packages dedicated to plant architecture analysis and visualisation (MTG and PlantGL from the OpenAlea platform). This new approach was developed on the uprooted root systems of two perennial species: grapevine and maritime pine. Their robustness was evaluated by comparing root traits estimated by this pipeline to root traits measured manually or estimated by a reference technique (semi-automated 3D digitizing, used on maritime pine root systems [1]). With this pipeline, we have planned to characterize the RSA of different rootstock genotypes, from different plantation types, soil management or water treatments, and at several developmental stages. All these data will be used to calibrate a functional-structural root model to facilitate the selection of plant material aimed to overcome the negative effects of climate change

A muscadine locus confers resistance to predominant species of grapevine root-knot nematodes (Meloidogyne spp.) including virulent populations

Root-knot nematodes (RKNs) Meloidogyne spp. are extremely polyphagous pests and four species severely affect grapevines throughout the world: M. arenaria, M. incognita, M. javanica and M. ethiopica. Californian populations of M. arenaria and M. incognita are reported to be virulent to widely used rootstocks and to the rootstock ‘Harmony’ in particular. Breeding RKNs-resistant grape rootstocks is a promising alternative to highly toxic nematicides. Muscadine (Vitis rotundifolia syn. Muscadinia rotundifolia) is a resistance (R) source with undercharacterised genetics. To this end, we used a segregating progeny between the RKN-resistant Vitis x Muscadinia accession ‘VRH8771’ from the muscadine source ‘NC184-4’ and the RKN-susceptible V. vinifera cv. Cabernet-Sauvignon. We first phenotyped its resistance to isolates of the i) M. arenaria, ii) M. incognita and iii) M. javanica species, and then to iv) two mixed Harmony-virulent Californian populations of M. arenaria and M. incognita. Finally, we created an isolate of M. arenaria and M. incognita from these Harmony populations and phenotyped the progeny to each of them [v) and vi)], and to vii) an isolate of M. ethiopica. The resistance phenotype of all the progeny’s individuals was independent of the RKN isolates or populations used. Resistance was mapped in a region of chromosome 18 in VRH8771, supporting the hypothesis that it is conferred by a single gene with an unprecedented wide spectrum in grapevine, including Harmony-virulent isolates. This dominant gene, referred to as MsppR1, is linked to the telomeric QTL XiR4 for X. index resistance from the same source. Additionally, plant mortality data showed that MsppR1-resistant material expressed a high-level resistance to the Harmony-virulent isolates. Our results are a first step towards the development of marker-assisted breeding using SSR and SNP markers for resistance to RKNs in accession VRH8771. © 2023, International Viticulture and Enology Society. All rights reserved

Unusual Transmission of Plasmodium falciparum, Bordeaux, France, 2009

Plasmodium falciparum malaria is usually transmitted by mosquitoes. We report 2 cases in France transmitted by other modes: occupational blood exposure and blood transfusion. Even where malaria is not endemic, it should be considered as a cause of unexplained acute fever

Xiphinema index-resistant grapevine materials derived from muscadine are also resistant to a population of X. diversicaudatum

Grapevine is severely affected by two major nepoviruses that cause grapevine degeneration: the grapevine fanleaf virus (GFLV) and the arabis mosaic virus (ArMV), specifically transmitted by the dagger nematodes Xiphinema index and X. diversicaudatum, respectively. While natural resistance to X. index has been shown to be a promising alternative for controlling X. index and GFLV transmission, the resistance interaction between X. diversicaudatum and grapevine has not yet been documented. In the present study, we evaluated the host suitability to X. diversicaudatum in materials previously characterised for their resistance to X. index. Two X. index-resistant accessions VRH8771 (F1 hybrid) and Nemadex Alain Bouquet (BC1 hybrid) derived from muscadine, together with the X. index-susceptible reference accession V. vinifera cv. Cabernet-Sauvignon and the X. index-resistant reference accession V. riparia ‘10128’, were challenged with a X. diversicaudatum population obtained from woody host plants and a reference isolate of X. index. The reproduction factors of X. diversicaudatum and its numbers per gram of roots paralleled those of X. index, showing a resistance interaction to the population of the former species and suggesting that resistance determinants to both nematode vectors might be the same or linked. Nevertheless, these two criteria illustrated a poorer host suitability of grapevine materials to this X. diversicaudatum population than to X. index

BMC Plant Biol

Combining innovation in vineyard management andgenetic diversity for a sustainable European viticultur

Long term effects of nitrogen and water supply on confered vigour and yield by SO4 and Riparia gloire de Montpellier rootstocks

Aims: the present study was designed to test the hypothesis according to which rootstock effects on scion growth and yield are related to fundamental physiological traits which are expressed consistently and independently of environmental conditions. Methods and results: Pruning weights and yield components from two independent rootstock experiments are reported. In the first experiment, the effect of two levels (30 and 70 kgN/ha/year) was studied during 15 years on Cabernet-Sauvignon vines grafted onto SO4 and Riparia Gloire de Montpellier (RGM). In the second one, Cabernet-Sauvignon and Merlot vines grafted on SO4 and RGM were submitted to two levels of soil fertility shortly after plantation: control and high (100 kgN/ha/year + irrigation) and data from the plantation to year 6 were recorded. In both experiments, vine vigour and yield were significantly affected by rootstocks and fertilisation/irrigation treatments. No interaction was recorded. The devigorating effect of RGM in comparison to SO4 was observed in both experiments, regardless of other parameters. Cabernet-Sauvignon was more affected by rootstock than Merlot. Conclusion: Rootstock effects on vine vegetative and reproductive development were consistently expressed, indicating that scion-rootstock interactions are governed not only by adaptative, but also by specific physiological traits. Significance and impact of study: This work provides information on scion-rootstock interactions which may be useful in rootstock breeding programs and may help to better choose the rootstock according to the scion and the environment

3D root system architecture of woody plant can be assessed using structure from motion photogrammetry

BackgroundPlant functioning relies on root system architecture (RSA), which can be best studied from a 3D database of root axes and segments. Most of such databases in woody plants grown in the field have been set up by semi-automatic digitising, using a low magnetic field 3D digitizer. As an alternative, Structure from Motion (SfM; photogrammetric range imaging technique) may require less manpower and produce more accurate data. However, no study offers a validated pipeline to obtain a 3D root system architecture database from SfM.Objective / Research question / HypothesisWe aim to propose a validated methodology to assess rapidly 3D root system architecture in woody plants using SfM.Material and methodsFour 5 m high pines (Pinus pinaster) and four one-year-old grapevines (Vitis riparia) were uprooted. The RSA was captured using SfM and segmentation to get axes and segments was performed with the plant structures reconstruction software (PlantScan3D) and two packages dedicated to plant architecture analysis and visualisation (MTG and PlantGL from the OpenAlea platform). This pipeline was evaluated by comparing root traits estimated by SfM to root traits measured manually (i.e. length, diameter and volume of 100 root samples from different root types) and computed from 3D digitizing.ResultsSfM measurements required six times less manpower than semi-automated 3D digitizing measurements. The root traits estimated by the SfM pipeline (e.g. length, diameter and volume of root samples) were in very good agreement with the manual measurements. However, diameters of fine roots (i.e. less than 2 mm diameter) were overestimated. They were corrected using the pipe model to compute architectural traits. The number, total length and total volume of the first- and the second-order root estimated by SfM were similar to those estimated by 3D digitizing. On the contrary, the number of third- and fourth-order roots was higher in the root system captured by SfM.DiscussionThe SfM combined with the PlantScan3D and OpenAlea packages provided a suitable approach and environment to characterize the root system architecture. We show that the accuracy of 3D data obtained with SfM is similar to that estimated manually, except for roots less than 2 mm in diameter for which corrections have been necessary. Root systems captured from SfM were similar to those measured by 3D digitizing. SfM captured a higher number of small and fine roots of high root orders (third- and four-order root). SfM can save manpower by providing precise databases of 3D-RSA in woody plant agronomic experiments where around a hundred roots have to be measured. For biomechanical application, an assessment of ovalisation (tridimensional diameter variation of the axes) is still needed, and it is not possible to deal with a too large number of non-rigid roots.Content Snapshot (max. 250 characters, excluding spaces)We aim to propose a validated methodology to assess rapidly 3D root system architecture, getting axes and segments, using Structure from Motion in woody plants grown in the field. An accurate pipeline has been setup for SfM, giving similar results to manual measurements and 3D-digitizing

3D root system architecture of woody plant can be assessed using structure from motion photogrammetry

BackgroundPlant functioning relies on root system architecture (RSA), which can be best studied from a 3D database of root axes and segments. Most of such databases in woody plants grown in the field have been set up by semi-automatic digitising, using a low magnetic field 3D digitizer. As an alternative, Structure from Motion (SfM; photogrammetric range imaging technique) may require less manpower and produce more accurate data. However, no study offers a validated pipeline to obtain a 3D root system architecture database from SfM.Objective / Research question / HypothesisWe aim to propose a validated methodology to assess rapidly 3D root system architecture in woody plants using SfM.Material and methodsFour 5 m high pines (Pinus pinaster) and four one-year-old grapevines (Vitis riparia) were uprooted. The RSA was captured using SfM and segmentation to get axes and segments was performed with the plant structures reconstruction software (PlantScan3D) and two packages dedicated to plant architecture analysis and visualisation (MTG and PlantGL from the OpenAlea platform). This pipeline was evaluated by comparing root traits estimated by SfM to root traits measured manually (i.e. length, diameter and volume of 100 root samples from different root types) and computed from 3D digitizing.ResultsSfM measurements required six times less manpower than semi-automated 3D digitizing measurements. The root traits estimated by the SfM pipeline (e.g. length, diameter and volume of root samples) were in very good agreement with the manual measurements. However, diameters of fine roots (i.e. less than 2 mm diameter) were overestimated. They were corrected using the pipe model to compute architectural traits. The number, total length and total volume of the first- and the second-order root estimated by SfM were similar to those estimated by 3D digitizing. On the contrary, the number of third- and fourth-order roots was higher in the root system captured by SfM.DiscussionThe SfM combined with the PlantScan3D and OpenAlea packages provided a suitable approach and environment to characterize the root system architecture. We show that the accuracy of 3D data obtained with SfM is similar to that estimated manually, except for roots less than 2 mm in diameter for which corrections have been necessary. Root systems captured from SfM were similar to those measured by 3D digitizing. SfM captured a higher number of small and fine roots of high root orders (third- and four-order root). SfM can save manpower by providing precise databases of 3D-RSA in woody plant agronomic experiments where around a hundred roots have to be measured. For biomechanical application, an assessment of ovalisation (tridimensional diameter variation of the axes) is still needed, and it is not possible to deal with a too large number of non-rigid roots.Content Snapshot (max. 250 characters, excluding spaces)We aim to propose a validated methodology to assess rapidly 3D root system architecture, getting axes and segments, using Structure from Motion in woody plants grown in the field. An accurate pipeline has been setup for SfM, giving similar results to manual measurements and 3D-digitizing