Mitotic activity in lemon fruit explants (Citrus limon L.) incubated on a calcium-potassium-sucrose medium

1974 ◽  
Vol 30 (7) ◽  
pp. 749-751 ◽  
Author(s):  
H. A. Kordan
Keyword(s):  
Mitotic Activity ◽  
Citrus Limon ◽  
Lemon Fruit ◽  
Sucrose Medium ◽  
Fruit Explants

scholarly journals First Report of Postharvest Blue Mold decay caused by Penicillium expansum on Lemon (Citrus limon) fruit in China

Plant Disease ◽  
2021 ◽  
Author(s):  
Ibatsam Khokhar ◽  
Jianming Chen ◽  
Junhuan Wang ◽  
Yang Jia ◽  
Yanchun Yan ◽  
...  
Keyword(s):  
Morphological Characteristics ◽  
Its Region ◽  
Penicillium Expansum ◽  
Citrus Limon ◽  
Conidial Suspension ◽  
Blue Mold ◽  
Causal Organism ◽  
Lemon Fruit ◽  
First Report ◽  
Fungal Isolates

Lemon (Citrus limon) is one of the most important commercial (both dried and fresh) citrus fruits in China. In the spring of 2019, postharvest blue mold decay was observed at an incidence of 3-5% on lemon fruit at the local markets in Beijing, China. Fruit lesions were circular, brown, soft, and watery, and rapidly expanded at 25°C. To isolate the causal organism, small pieces (2 mm3) were cut from the lesions, surface-sterilized for 1 min in 1.5% NaOCl, rinsed three times with sterilized water, dried with sterile filter paper, placed onto potato dextrose agar (PDA) medium, and incubated at 25°C for 6 days. Eight morphologically similar single-colony fungal isolates were recovered from six lemon fruit. Colony surfaces were bluish-green on the upper surface and cream to yellow-brown one the reverse. Hyphae on colony margins were entirely subsurface and cream in color. Mycelium was highly branched, septate, and colorless, and conidiophores were 250 to 450 × 3.0 to 4.0 µm in size. Stipe of conidiophores were smooth-walled, bearing terminal penicilli, typically terverticillate or less commonly birverticillate, rami occurring singly, 16 to 23 × 3.0 to 4.0 µm, metulae in 3 to 6, measuring 12 to 15 × 3.0 to 4.0 µm. Phialides were ampulliform to almost cylindrical, in verticils of 5 to 8, measuring 8 to 11 × 2.5 to 3.2 µm with collula. Conidia were smooth-walled, ellipsoidal, measuring 3.0 to 3.5 × 2.5 to 3.0 µm. According to morphological characteristics, the fungus was identified as Penicillium expansum (Visagie et al. 2014). For molecular identification, genomic DNA of eight fungal isolates was extracted, regions of the beta-tubulin (TUB), and calmodulin (CAL) genes and ITS region, were amplified using Bt2a/Bt2b, CAL-228F/ CAL-737, and ITS1/ITS4 primers respectively. Obtained sequences of all isolates were identical to sequences of the representative isolate YC-IK12, which was submitted in the GenBank. BLAST results of YC-IK12 sequences (ITS; MT856700: TUB; MT856958: CAL; MT856959) showed 98 to 100% similarity with P. expansum accessions (NR-077154, LN896428, JX141581). For pathogenicity tests, 10 μl of conidial suspension (10 × 105 conidia/ml) from seven-day-old YC-IK12 culture was inoculated using a sterilized needle into the surface of each five asymptomatic disinfected lemons. As a control, three lemons were inoculated using sterile distilled water. All inoculated lemons were placed in plastic containers and incubated at 25°C for 7 days. Decay lesions, identical to the original observations, developed on all inoculated lemons, while control lemons remained asymptomatic. Fungus re-isolated from the inoculated lemon was identified as P. expansum on the basis morphology and Bt2a/Bt2b, CAL-228F/ CAL-737, and ITS1/ITS4 sequences. Previously, Penicillium spp. including P. expansum have been reported as post-harvest pathogens on various Citrus spp. (Louw & Korsten 2015). However, P. digitatum has been reported on lemons and P. expansum has been reported on stored Kiwifruit (Actinidia arguta), Malus, and Pyrus species in China (Tai, 1979; Wang et al. 2015). To our knowledge, this is the first report of blue mold caused by P. expansum on lemons in China. References Louw, J. P., Korsten, L. 2015. Plant Dis. 99:21-30. Tai, F.L. 1979. Sylloge Fungorum Sinicorum. Sci. Press, Acad. Sin., Peking, 1527 pages. 8097 Visagie, C.M. et al. 2014. Studies. Mycol.78: 343. Wang, C. W. et al. 2015. Plant Dis. 99:1037.

scholarly journals In vitro Antimicrobial Potency of Lemon Fruit (Citrus limon) Extract on Salmonella typhi

2020 ◽  
Vol 11 (2) ◽  
pp. 69
Author(s):  
Farhan Haidar Fazlur Rahman ◽  
Lindawati Alimsardjono ◽  
Sunarni Zakaria
Keyword(s):  
Agar Plate ◽  
Antimicrobial Effect ◽  
Salmonella Typhi ◽  
Citrus Limon ◽  
Lemon Fruit ◽  
Mueller Hinton ◽  
Antibacterial Spectrum ◽  
Mueller Hinton Broth

Introduction: This study aimed to evaluate minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of lemon fruit (Citrus limon) extract in inhibiting Salmonella typhi growth in vitro.Methods: This research was categorized as a laboratory experimental study. Lemon fruit (Citrus limon) extract was prepared with concentration as follows: 100.000 ppm, 50.000 ppm, 25.000 ppm, 12.500 ppm, 6.250 ppm, 3.125 ppm, 1.562 ppm, 781 ppm, and 390 ppm. Dilution tests with Mueller-Hinton broth medium were performed to determine the MIC. After 24 hours of incubation, isolated Salmonella typhi inside the tube was inoculated back in MacConkey agar plate medium to determine the MBC. Replications were conducted 3 times according to Federer’s formula.Results: MIC of lemon fruit (Citrus limon) extract to Salmonella typhi was determined at 3.125 ppm. Meanwhile, MBC was determined at 6.250 ppm.Conclusion: This study showed the potential antimicrobial effect of lemon fruit (Citrus limon) extract against Salmonella typhi in-vitro. Further studies are still needed to determine its efficacy and safety in vivo and also its full antibacterial spectrum. 

scholarly journals Low temperature modulates natural peel degreening in lemon fruit independently of endogenous ethylene

2020 ◽  
Vol 71 (16) ◽  
pp. 4778-4796
Author(s):  
Oscar W Mitalo ◽  
Takumi Otsuki ◽  
Rui Okada ◽  
Saeka Obitsu ◽  
Kanae Masuda ◽  
...  
Keyword(s):  
Low Temperature ◽  
Citrus Fruit ◽  
Citrus Limon ◽  
Lemon Fruit ◽  
Ethylene Treatment ◽  
Low Temperature Storage ◽  
Endogenous Ethylene ◽  
Significant Expression ◽  
Storage Temperatures ◽  
Temperature Storage

Abstract Peel degreening is an important aspect of fruit ripening in many citrus fruit, and previous studies have shown that it can be advanced by ethylene treatment or by low-temperature storage. However, the important regulators and pathways involved in natural peel degreening remain largely unknown. To determine how natural peel degreening is regulated in lemon fruit (Citrus limon), we studied transcriptome and physiochemical changes in the flavedo in response to ethylene treatment and low temperatures. Treatment with ethylene induced rapid peel degreening, which was strongly inhibited by the ethylene antagonist, 1-methylcyclopropene (1-MCP). Compared with 25 ºC, moderately low storage temperatures of 5–20 °C also triggered peel degreening. Surprisingly, repeated 1-MCP treatments failed to inhibit the peel degreening induced by low temperature. Transcriptome analysis revealed that low temperature and ethylene independently regulated genes associated with chlorophyll degradation, carotenoid metabolism, photosystem proteins, phytohormone biosynthesis and signalling, and transcription factors. Peel degreening of fruit on trees occurred in association with drops in ambient temperature, and it coincided with the differential expression of low temperature-regulated genes. In contrast, genes that were uniquely regulated by ethylene showed no significant expression changes during on-tree peel degreening. Based on these findings, we hypothesize that low temperature plays a prominent role in regulating natural peel degreening independently of ethylene in citrus fruit.

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