Table 2.
Morphological characters and dimensions (μm), cardinal temperatures (°C) and temperature-growth relations (mm/d) on V8A of Phytophthora castanetorum, P. tyrrhenica, P. tubulina, P. vulcanica and their closest relatives in phylogenetic Clades 7a and 12, respectively. Most discriminating characters are highlighted in bold.
| P. castanetorum | P. tubulina | P. quercina | P. tyrrhenica | P. vulcanica | P. uliginosa | P. europaea | P. flexuosa | |
|---|---|---|---|---|---|---|---|---|
| No. of isolates | 9 | 5 | 10 b | 7 | 5 | 3a | 7a | 3a |
| Sporangia | ovoid, subglobose, obpyriform, globose, (ellipsoid, distorted) | ovoid, obpyriform, distorted, (globose, subglobose, ellipsoid, limoniform) | subglobose, ovoid, obpyriform, peanut, ampulliform, distorted | elongated ellipsoid, elongated ovoid, elongated limoniform | ovoid, ellipsoid, (obpyriform, pyriform) | ellipsoid, ovoid, peanut-shaped, (obpyriform, limoniform) | ovoid, obpyriform, ellipsoid, (subglobose), | ovoid, ellipsoid, (obpyriform, limoniform) |
| apex | 77.4 % papillate, 14.9 % semipapillate; 7.7 % nonpapillate, 4.9 % curved | 78 % mono-, bi- or tripapillate; 13.3 % semi-papillate; 8.7 % non-papillate, 4.9 % curved | all papillate, some bi- and tripapillate; often curved | nonpapillate | nonpapillate | nonpapillate | nonpapillate, often pointed | |
| lxb mean | 47.0±5.7 x 36.6±3.7 | 51.6±9.8 x 37.3±7.0 | 42.4±11.5 x 29.3±13.8 | 68.4±1.7 x 28.9±1.9 | 57.3±8.7 x 34.5±4.2 | 67.0±8.5 x 42.4±6.4 | 63.7±16.9 x 44.6±8.3 | 56.1±7.4 x 36.7±5.2 |
| range of isolate means | 44.2–48.1 x 35.4–38.3 | 43.3–57.8 x 31.2–45.0 | 36.0–49.2 x 23.3–33.7 | 66.1–70.0 x 27.5–31.9 | 53.6–61.0 x 31.8–36.4 | 65.7–70.3 x 30.9–44.4 | 50.0–78.9 x 36.7–51.2 | 53.3–58.6 x 33.9–39.4 |
| total range | 27.1–74.5 x 18.1–47.9 | 29.5–98.5 x 19.2–59.2 | 18.8–112.5 x 13.8–47.5 | 45.3–110.2 x 16.2–39.4 | 35.5–80.7 x 22.5–42.9 | 41.1–85.0 x 24.8–56.9 | 23.6–124.3 x 21.9–67.3 | 34.9–74.8 x 22.8–49.7 |
| l/b ratio | 1.29 ± 0.15 | 1.40 ± 0.18 | 1.45 ± 0.37 | 2.40 ± 0.18 | 1.67 ± 0.22 | 1.60 ± 0.19 | 1.42 ± 0.19 | 1.54 ± 0.18 |
| caducity | – | rare | – | – | – | – | – | – |
| lateral insertion | 37.7 % | 22.4 % | frequent | |||||
| exit pores | 7.0 ± 1.1 | 6.4 ± 1.2 | 6.5 ± 1.2 | 12.1 ± 2.4 | 17.0 ± 3.0 | 15.4 ± 3.4 | 19.3 ± 4.7 | 19.7 ± 3.4 |
| zoospore cysts | 9.2 ± 1.0 | 11.7 ± 1.8 | 9.5 (7.1–12.9) | 14.6 ± 2.3 | 10.0 ± 1.2 | 11.9 ± 1.8 | 15.3 ± 2.0 | 13.3 ± 1.3 |
| Breeding system | homothallic | homothallic | homothallic | homothallic | homothallic | homothallic | homothallic | homothallic |
| Oogonia | ||||||||
| mean diam | 32.9 ± 3.0 | 29.2 ± 4.4 | 29.4 ± 4.1 | 37.2 ± 3.3 | 35.8 ± 3.6 | 46.2 ± 7.5 | 37.3 ± 5.4 | 36.8 ± 3.3 |
| range of isolate means | 30.5–34.4 | 25.4-30.1 | 25.8–32.0 | 36.8–40.9 | 33.6–36.5 | 41.6–53.3 | 34.4–39.9 | 36.0-38.3 |
| total range | 24.3–41.7 | 16.5–42.5 | 19.0–45.0 | 25.0–39.3 | 23.0–46.0 | 17.9–65.5 | 19.2–48.4 | 25.7–42.8 |
| tapering base | 61.3 % (40–86 %) | 48.7 % (30–78 %) | n.a. | – | 37.3 % (8–60 %) | – | 60.0 % (52–81 %) | 47.9 % (32–58 %) |
| elongated | 65.4 % (50–82 %) | 59.5 % (36–86 %) | 45 % (10–86 %) | – | 44.8 % (8–80 %) | – | 21.3 % (12–34 %) | 19.7 % (4–36 %) |
| tubular | – | 24.5 % (21–28 %) | – | – | – | – | – | – |
| excentric | 6.7 % (2–20 %) | 5.0 % (2–8 %) | n.a. | – | 20.9 % (9–46 %) | – | 4.0 % (0–8 %) | 5.3 % (2–10 %) |
| smooth-walled | 100 % | 100 % | 100 % | 100 % | 100 % | 100 % | 100 % | 34.4 % (19–48 %) |
| Oospores | ||||||||
| plerotic oospores | 64.3 % (50–83 %) | 44 % (24–76 %) | mostly aplerotic | >99 % (99–100 %) | 27.3 % (10–45 %) | 30.0 % (12-46 %) | 46.3 % (38–53 %) | >99 % (99–100 %) |
| mean diam | 28.7 ± 2.6 | 26.1 ± 3.7 | 24.7 ± 2.6 | 33.7±1.3 | 30.5 ± 3.2 | 41.3±6.1 | 33.2 ± 5.3 | 32.2 ± 2.7 |
| Total range | 21.9–38.8 | 15.7–36.3 | 18.0–30.0 | 24.6–39.9 | 19.7-38.2 | 12.5-55.0 | 16.3–45.1 | 22.7–37.7 |
| wall diam | 3.1 ± 0.49 | 2.0 ± 0.6 | 2.4 ± 0.56 | 2.9 ± 1.5 | 2.4 ± 0.4 | 4.2 ± 0.7 | 2.5 ± 0.7 | 3.1 ± 0.5 |
| oospore wall index | 0.51 ± 0.05 | 0.38 ± 0.08 | 0.44 ± 0.1 | 0.41 ± 0.03 | 0.40 ± 0.06 | 0.49 ± 0.07 | 0.38 ± 0.06 | 0.47 ± 0.06 |
| Abortion rate | 21.5 % (18–29 %) | 72.3 % (40–91 %) | <10 % | 5 % (3–7 %) | 52.8 % (0–80 %) | 6.2 % (3-10 %) | 24.9 % (18–31 %) | 1.7 % (1–2 %) |
| Antheridia | 99 % paragynous | 100 % paragynous | 100 % paragynous | 100 % paragynous | 4.7 % amphigynous | 100 % paragynous | 100 % paragynous | 100 % paragynous |
| size | 14.0±2.3 x 10.2±1.6 | 14.9±3.1 x 10.9±1.7 | 16.6±6.3 x 12.7±2.5 | 16.9±4.6 x 12.8±0.13 | 16.3±3.1 x 12.6±2.3 | 16.9±3.1 x 13.3±2.5 | 13.6±2.6 x 10.8±2.1 | 13.4±2.1 x 10.0±1.7 |
| Chlamydospores | globose | – | rare, in some isolates | – | – | – | – | – |
| mean diam | 29.5 ± 4.9 (17.7–47.0) | 17–35 | ||||||
| Hyphae | Sympodial branching with protruding tip of mother hypha | Sympodial branching with protruding tip of mother hypha | Sympodial branching with protruding tip of mother hypha | Often inflated tubular or club-shabed | Coralloid | |||
| Hyphal aggregations | – | – | – | – | + | (+) | – | – |
| Hyphal swellings | in water; globose, subglobose, limoniform; some catenulate | in water; subglobose, triangular; some catenulate | – | in water; subglobose, irregular, catenulate | in water; subglobose, irregular, catenulate | in water; subglobose, irregular, catenulate | – | – |
| Maximum temperature | 25–<30 | 25–<30 | 27.5 | 25–<30 | 25–<30 | 25 | 30–<35 | 35 |
| Optimum temperature | 20 | 20 | 25 | 25 | 15 | 20 | 25 | 25 |
| Growth rate at optimum | 2.9 ± 0.91 | 1.7 ± 1.0 | 3.7 | 1.1 ± 0.4 | 1.0 ± 0.1 | 1.2 ± 0.2 | 4.9 ± 0.53 | 4.7 ± 0.61 |
| Growth rate at 20°C | 2.7 ± 0.75 | 1.7 ± 1.0 | 3.3 | 1.5 ± 0.3 | 0.9 ± 0.04 | 1.2 ± 0.2 | 4.4 ± 0.59 | 4.4 ± 0.56 |
– = character not observed; + = character observed; n.a. = not available.
a Data from Jung et al. (2017b).
b Morphological and morphometric data from Jung et al. (1999); standard deviations of all morphometric data, oospore wall diameter and oospore wall index calculated from original dataset.