1. RESULTS AND DISCUSSION
Quantum-Dot LED Technique for in vitro Mycelial Suppression of Plant Fungal Pathogens
Sun Kumar Gurung, Mahesh Adhikari, Hyun Gu Lee, Setu Bazie, San Kosol and Youn Su Lee*
Division of Biological Resource Sciences, Kangwon National University, Chuncheon 24341, Korea
ABSTRACT
Quantum dot Light Emitting Diodes (QD-LED) is an emerging technology of nano-scale crystal technique which serves as an alternative for applications such as plant disease control technology. This study was carried out to screen and evaluate the different QD-LED in suppression of plant fungal pathogens. Red (660 nm, PPFD 102.5), Blue (450 nm, PPFD 105.8), Narrow Red (Blue and red) (104.5) and Wide Red (PPFD 104.3) lights were used against six plant pathogenic fungi (Rhizoctonia solani, Sclerotinia minor, Sclerotinia sclerotiorum, Fusarium oxysporum, Phytophthora dreschsleri and Botrytis cinerea). Experiments were conducted inside QD-LED chamber with the adjustment of different light wave length. Plates were kept at two different heights (15 cm and 50 cm of 100 W) in all the light conditions. Results revealed that, in 15 cm height, Blue (105.8) light suppressed the mycelia of Sclerotinia minor by 74 % over control plates. In addition, plates exposed with Wide Red (104.3) suppressed the mycelia of Botrytis cinerea by 73.8 %. Control plates were grown fully attaining a diameter of 8.5 cm. Furthermore, in 50 cm height, Wide Red (104.3) reduced the mycelial growth of the fungal pathogen, Botrytis cinerea by %. Our results suggests that, suppressive effect is higher when fungal pathogens is exposed to QD-LED from short height. This study shows the applicability of the multi-wavelength QD-LED for the mycelial suppression of the plant fungal pathogens.
MATERIALS AND METHODS
Potato dextrose agar (PDA) media was prepared for the culture of fungal pathogens. In addition, V8 juice agar was prepared for Phytophthora dreschsleri.
All the tested fungal pathogens were kept under different light conditions including QD-LED.
Mycelial growth of the tested fungal pathogens were observed daily.
Picture and diameter of mycelial growth was recorded for each tested fungal pathogens after the complete growth of mycelia at control plates.
Fig. 1. Chamber with different light conditions including QD-LED
RESULTS AND DISCUSSION D
Fig.3. 2.Tests with fungal pathogens (I) from left to right, Rhizoctonia solani, Phytophthora dreschsleri, Sclerotinia sclerotiorum, (II) from left to right, Sclerotinia minor, Botrytis cinerea and Fusarium oxysporum) growth in QD-LED light box with 50 cm height from the light source (100 W) (A) Tri-color fluorescent (104.3nm) (B) Blue (450nm), (C) Red (660nm), (D) Narrow red, (E) Wide red (M1) (F), Wide red (M2).
Fig. 2.Tests with fungal pathogens (I) from left to right, Rhizoctonia solani, Phytophthora dreschsleri, Sclerotinia sclerotiorum, (II) from left to right, Sclerotinia minor, Botrytis cinerea and Fusarium oxysporum) growth in QD-LED light box with 15 cm height from the light source (100 W) (A) Tri-color fluorescent (104.3nm) (B) Blue (450nm), (C) Red (660nm), (D) Narrow red, (E) Wide red (M1), (F) Wide red (M2).
Table.2. Mycelial growth of tested fungal pathogens under different QD-LED conditions (50 cm height from the light source).
Table.1. Mycelial growth of tested fungal pathogens under different QD-LED conditions (15 cm height from the light source).
Fungi
R. sol
P. dre
S. scl
S. min
B. cin
F. oxy
Tri-color fluorescent
(삼파장 형광등)
8.50
7.88
6.02
3.77
6.90
BLUE(450nm)
7.35
2.21
2.25
6.84
RED(660nm)
8.19
6.40
4.53
6.87
Narrow RED
7.93
3.09
3.02
6.83
Wide RED(M1)
7.18
5.42
6.74
Wide RED(M2)
6.78
3.44
2.22
6.69
Control
8.5
8.47
7.30
*R. sol, P. dre, B. cin were grown in 7 days. S. Scl, S. min were grown in 4 days and F. oxy was grown in 2 weeks.
Fungi
R. sol
P. dre
S. scl
S. min
B. cin
F. oxy
Tri-color fluorescent
(삼파장 형광등)
8.50
8.30
8.10
7.96
7.50
BLUE(450nm)
8.00
7.40
7.04
7.30
RED(660nm)
7.90
7.00
7.80
7.29
Narrow RED
6.34
7.32
Wide RED(M1)
7.03
7.81
Wide RED(M2)
6.03
7.33
Control
7.77
*R. sol, P. dre, B. cin were grown in 7 days. S. Scl, S. min were grown in 4 days and F. oxy was grown in 2 weeks.
Fig.5. Mycelial growth of tested fungal pathogens under different QD-LED conditions.
Fig. 4. Mycelial growth of tested fungal pathogens under different QD-LED conditions.
CONCLUSION
Mycelial growth suppression of the tested fungal pathogens were varied with the QD-LED wavelengths.
Highest reduction in mycelial growth of the tested fungal pathogens was recorded in Sclerotinia minor in Blue light with 74.0%.
Wide red (M1) suppressed the mycelia of Botrytis cinerea by 73.8%.