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15 pages, 4535 KiB

Open AccessArticle

Induction of Polyploidy in Citrus Rootstocks through In Vitro Colchicine Treatment of Seed-Derived Explants

by Vijayakumari Narukulla, Yogesh Lahane, Krutika Fiske, Shashi Pandey and Vasileios Ziogas

Agronomy 2023, 13(6), 1442; https://doi.org/10.3390/agronomy13061442 - 24 May 2023

Cited by 7 | Viewed by 3059

Polyploidy, frequently observed in citrus species, aids in achieving better adaptation to environmental stresses. In this context, the current work aims to develop stable tetraploids in citrus rootstock cultivars, viz., Rough lemon, Rangpur lime and Alemow, through in vitro colchicine treatments. Seed-derived explants were obtained by culturing sterile seeds on MS basal media. Seedlings with a size of 5–8 mm (hypocotyl) were exposed to colchicine treatment. After treatment, the surviving seedlings were minigrafted onto six-month-old rootstock for better growth. Colchicine concentrations of 0.1%, 0.2%, 0.3% and control for durations of 16 or 24 h were tested with respect to the induction of polyploidisation. Treatment with 0.1% colchicine for 24 h resulted in high rates of mutation for polyploidisation and showed the highest tetraploid induction percentage (18.3%) in all the rootstock cultivars. High colchicine concentration and long exposure time decreased the survival of the observed seedlings. Flow cytometry and cytological methods were used for confirmation of autotetraploidy in the analysed samples. The surviving seedlings were identified on the basis of morphological and cytological variables, such as leaf area and stomata size, which significantly increased with increasing ploidy level. The proposed method was found to be an effective way to induce the polyploidy in Rangpur lime, Rough lemon and Alemow rootstocks. Full article

(This article belongs to the Special Issue Fruit Growing: Production Practices and Post-Harvest Management)

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17 pages, 1697 KiB

Open AccessArticle

Chemotactic Responses of Xanthomonas with Different Host Ranges

by Marta Sena-Vélez, Elisa Ferragud, Cristina Redondo, James H. Graham and Jaime Cubero

Microorganisms 2023, 11(1), 43; https://doi.org/10.3390/microorganisms11010043 - 22 Dec 2022

Cited by 3 | Viewed by 2271

Abstract

Xanthomonas citri pv. citri (Xcc) (X. citri subsp. citri) type A is the causal agent of citrus bacterial canker (CBC) on most Citrus spp. and close relatives. Two narrow-host-range strains of Xcc, A^w and A*, from Florida and Southwest Asia, respectively, infect only Mexican lime (Citrus aurantifolia) and alemow (C. macrophylla). In the initial stage of infection, these xanthomonads enter via stomata to reach the apoplast. Herein, we investigated the differences in chemotactic responses for wide and narrow-host-range strains of Xcc A, X. euvesicatoria pv. citrumelonis (X. alfalfae subsp. citrumelonis), the causal agent of citrus bacterial spot, and X. campestris pv. campestris, the crucifer black rot pathogen. These strains of Xanthomonas were compared for carbon source use, the chemotactic responses toward carbon compounds, chemotaxis sensor content, and responses to apoplastic fluids from Citrus spp. and Chinese cabbage (Brassica pekinensis). Different chemotactic responses occurred for carbon sources and apoplastic fluids, depending on the Xanthomonas strain and the host plant from which the apoplastic fluid was derived. Differential chemotactic responses to carbon sources and citrus apoplasts suggest that these Xanthomonas strains sense host-specific signals that facilitate their location and entry of stomatal openings or wounds. Full article

(This article belongs to the Special Issue Plant Pathogenic Microorganisms: State-of-the-Art Research in Spain)

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9 pages, 1157 KiB

Open AccessFeature PaperArticle

Short-Term Waterlogging in Citrus Rootstocks

by Margarita Pérez-Jiménez and Olaya Pérez-Tornero

Plants 2021, 10(12), 2772; https://doi.org/10.3390/plants10122772 - 15 Dec 2021

Cited by 9 | Viewed by 3177

Abstract

Changes in climate are provoking flooding events that cause waterlogging in the fields. Citrus are mainly cultivated in areas with a high susceptibility to climate change. Therefore, it is vital to explore their responses to these events to anticipate future challenges by means of genetic improvement of the commercial rootstocks. In this experiment, three popular commercial rootstocks, namely ‘Cleopatra’ (C. reshni Hort. Ex Tanaka), C. macrophylla, and ‘Forner Alcaide no. 5′ (Citrus reshni Hort. Ex Tanaka × Poncirus trifoliata), were evaluated after being submitted to short-term waterlogging and a period of recovery of 7 days in each case. Photosynthesis rate and stomatal conductance decreased in ‘Cleopatra’, while in the other two genotypes they were maintained (C. macrophylla) or restored after recovery (‘Forner Alcaide no. 5′’). Relative water content and chlorophylls also decreased in ‘Cleopatra’. This indicates a deeper effect of flooding in ‘Cleopatra’, which suffered changes during flooding that were also sustained during the recovery phase. This did not occur in the other two rootstocks, since they showed signs of recovery for those parameters that decreased during waterlogging. Full article

(This article belongs to the Special Issue Selected papers from the XVI Congress of the Spanish Society of Horticultural Science (SECH))

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