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Idesia polycarpa from Sichuan is a valuable germplasm with high economic potential, but it faces variety scarcity. To address this, this study collected 16 varieties (lines), identifying IpHT1 as a promising parent due to its high oil content (38.5%) and red fruits. Polyploid induction via adding 0.50% colchicine to Murashige and Skoog (MS) medium yielded 520 IpHT1 mutagenized seedlings. Subsequently, flow cytometry (FCM) was performed on 401 morphologically variant seedlings which had been initially screened, resulting in the identification of 15 suspected triploids, 35 suspected tetraploids, and 3 chimeras. Furthermore, fluorescence in situ hybridization (FISH) analysis found that the probe (AG3T3)3 had terminal signals at both ends of each chromosome, allowing for the counting of 42 chromosomes in diploids and 84 in tetraploids. The probe 5S rDNA showed 2, 3, and 4 hybridization signals in the interphase nuclei of diploid, triploid, and tetraploid cells, respectively, but the probe (GAA)6 failed to produce any signal on I. polycarpa chromosomes. Ultimately, 18 polyploids were selected, including 7 triploids and 11 tetraploids. Triploids and tetraploids showed significant leaf morphological and physiological differences from diploids. Consequently, this study successfully established a polyploid breeding system for I. polycarpa, thereby enhancing its genetic diversity and breeding potential. [ABSTRACT FROM AUTHOR]

This study was conducted to evaluate the 5S rDNA site number, position, and origin of signal pattern diversity in 42 plant species using fluorescence in situ hybridization. The species were selected based on the discovery of karyotype rearrangement, or because 5S rDNA had not yet been explored the species. The chromosome number varied from 14 to 160, and the chromosome length ranged from 0.63 to 6.88 μm, with 21 species having small chromosomes (<3 μm). The chromosome numbers of three species and the 5S rDNA loci of nineteen species are reported for the first time. Six 5S rDNA signal pattern types were identified. The 5S rDNA varied and was abundant in signal site numbers (2–18), positions (distal, proximal, outside of chromosome arms), and even in signal intensity. Variation in the numbers and locations of 5S rDNA was observed in 20 species, whereas an extensive stable number and location of 5S rDNA was found in 22 species. The potential origin of the signal pattern diversity was proposed and discussed. These data characterized the variability of 5S rDNA within the karyotypes of the 42 species that exhibited chromosomal rearrangements and provided anchor points for genetic physical maps. [ABSTRACT FROM AUTHOR]

Fatsia japonica (Thunb.) Decne. & Planch. (Araliaceae), an evergreen shrub, is widely planted in urban settings at the south of the Yangtze river in China. Leaf-spot symptoms were observed on 120/200 F. japonica plants at Sichuan Agricultural University. Initially, yellowish spots appeared on the leaves and became white with age. The spots continued to expand with time developing irregular margins eventually encompassing the entire leaf. Eventually, diseased leaves became curled and died. Four single-spore isolates were obtained following Chomnunti et al. (2014). The colonies developed on potato dextrose agar (PDA) were white to grey with fluffy aerial hyphae. The base of the mycelium was yellow. On the host conidiomata circular to elliptical, measured 108-335 × 107-250 μm (n=20). Conidiophores were bell-shaped to cylindrical, hyaline, usually 1-celled, unbranched, 9.7-23.6(-28) × 3.5-5.5 μm (x̅ =16.5 × 4.6 μm, n=15). Conidia measured 12.5-17.6 × 5.1-7.9 μm (x̅ =14.9 × 6.7 μm, n=25), were hyaline, straight, unicellular, cylindrical. Appressoria formed abundantly on slides, measured 12.4-25.4(-29.6) × 6.3-18.4 μm (x̅ =18.9 × 13.4 μm, n=30), were dark brown to black, elliptical to irregular. Ascomata on PDA were brown to dark brown, global, covered by aerial mycelium, and setae were absent. Ascospores measured 13.2-19.1 × 4.0-6.1 μm (x̅ =16.0 × 4.8 μm, n=20), and one-celled, hyaline, slightly curved. The representative isolate SICAUCC 20-0010 was used for Genomic DNA extraction following the instructions of Plant Genomic DNA extraction kit TM (Tiangen, China), and the internal transcribed spacer ( ITS , MT393946), glyceraldehyde-3-phosphate dehydrogenase ( GAPDH , MT425977), beta-tubulin ( TUB2 , MT425978), chitin synthase ( CHS-1 , MT425976) and actin ( ACT , MT425975) genes were amplified with ITS5/ITS4 (White et al. 1990), GDF/GDR (Guerber et al. 2003), T1/Bt2b (O'Donnell et al. 1997), CHS-79F/CHS-354R and ACT-512F/ACT-783R (Carbone et al. 1999) primers, respectively. ITS , GAPDH , CHS-1 and ACT blast showed 100% homology with sequences of Colletotrichum karstii (Yang et al. 2011, Damm et al. 2012, Xu et al. 2019), viz. JQ005186 (555/555 bp), MK359214 (238/238 bp), JQ005360 (274/274 bp), MK359211 (269/269 bp), respectively. TUB2 showed 99.60% homology with sequences JQ005620 (495/497 bp). The fungus was identified as C. karstii based on morphology and a multigene phylogeny (Fig. 1). Four leaves from each of three healthy F. japonica plants were sprayed with a conidial suspension (1 × 10 5 conidia/ml) of the isolate SICAUCC 20-0010. Two additional mock-inoculated control plants were sprayed with sterile distilled water. Plants were incubated in a greenhouse at 26℃ and 90% relative humidity with a 12-h photoperiod. The leaves developed chlorotic lesions 6 days post-inoculation and by twenty-two days post-inoculation the remaining signs and symptoms had developed. No symptoms developed on the mock-inoculated controls. The fungus isolated from inoculated plants was morphologically identical to the original pathogen, fulfilling Koch's postulates. The anthracnose on F. japonica caused by C. fructicola and C. gloeosporioide have been reported in China (Wang 2007, Shi et al. 2017). However, this is the first report of anthracnose caused by C. karstii on F. japonica . Field observations indicated that this disease mainly occurs on old and weakened leaves. This disease affects the aesthetic appearance of the plants reducing their appeal as landscape plants.