• The Plant Pathology Journal
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• v.38 no.5
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• pp.425-431
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• 2022

Plant microbiota has influenced plant growth and physiology significantly. Plant and plant-associated microbes have flexible interactions that respond to changes in environmental conditions. These interactions can be adjusted to suit the requirements of the microbial community or the host physiology. In addition, it can be modified to suit microbiota structure or fixed by the host condition. However, no technology is realized yet to control mechanically manipulated plant microbiota structure. Here, we review step-by-step plant-associated microbial partnership from plant growth-promoting rhizobacteria to the microbiota structural modulation. Glutamic acid enriched the population of Streptomyces, a specific taxon in anthosphere microbiota community. Additionally, the population density of the microbes in the rhizosphere was also a positive response to glutamic acid treatment. Although many types of research are conducted on the structural revealing of plant microbiota, these concepts need to be further understood as to how the plant microbiota clusters are controlled or modulated at the community level. This review suggests that the intrinsic level of glutamic acid in planta is associated with the microbiota composition that the external supply of the biostimulant can modulate.

• Molecules and Cells
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• v.23 no.1
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• pp.72-79
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• 2007

Demand for low-input sustainable crop cultivation is increasing to meet the need for environment-friendly agriculture. Consequently, developing genotypes with high nutrient use efficiency is one of the major objectives of crop breeding programs. This study was conducted to identify QTLs for traits associated with physiological nitrogen use efficiency (PNUE). A recombinant inbred population (DT-RILs) between Dasanbyeo (a tongil type rice, derived from an indica ${\times}$ japonica cross and similar to indica in its genetic make-up) and TR22183 (a Chinese japonica variety) consisting of 166 $F_8$ lines was developed and used for mapping. A frame map of 1,409 cM containing 113 SSR and 103 STS markers with an average interval of 6.5 cM between adjacent marker loci was constructed using the DT-RILs. The RILs were cultivated in ordinary-N ($N-P_2O_5-K_2O=100-80-80kg/ha$) and low-N ($N-P_2O_5-K_2O=50-80-80kg/ha$) (100 kg/ha) conditions. PNUE was positively correlated with the harvest index and grain yield in both conditions. Twenty single QTLs (S-QTLs) and 58 pairs of epistatic loci (E-QTLs) were identified for the nitrogen concentration of grain, nitrogen concentration of straw, nitrogen content of shoot, harvest index, grain yield, straw yield and PNUE in both conditions. The phenotypic variance explained by these S-QTLs and E-QTLs ranged from 11.1 to 44.3% and from 16.0% to 63.6%, respectively. The total phenotypic variance explained by all the QTLs for each trait ranged from 35.8% to 71.3%, showing that the expression of PNUE and related characters depends signify- cantly upon genetic factors. Both S-QTLs and E-QTLs may be useful for marker-assisted selection (MAS) to develop higher PNUE genotypes.

• Journal of The Korean Society of Grassland and Forage Science
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• v.38 no.3
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• pp.175-179
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• 2018

Humic substances that can be obtained from coal resources such as leonardite in a bulk scale have been employed as crop stimulators and soil conditioners. The polymeric organics containing a variety of aromatic and aliphatic structures are known to activate plants in a multifunctional way, thus resulting in enhanced germination rate and abiotic stress resistance concomitant with induction of numerous genes and proteins. Although detailed structural-functional relationship of humic substances for plant stimulations has not been deciphered yet, cutting-edge analytical tools have unraveled critical features of humic architectures that could be linked to the action mechanisms of their plant stimulations. In this review article, we introduce key findings of humic structures and related biological functions that boost plant growth and abiotic stress resistance. Oxygen-based functional groups and plant hormone-like structures combined with labile and recalcitrant carbon backbones are believed to be critical moieties to induce plant stimulations. Some proteins such as HIGH-AFFINITY $K^+$ TRANSPORTER 1, phospholipase A2 and $H^+$-ATPase have been also recognized as key players that could be critically involved in humic substance-driven changes in plant physiology.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.6
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• pp.565-570
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• 2006

The viviparous germination (VG) with lodging caused the yield reduction and quality deterioration in rice. We carried out the evaluation of VG tolerance (on the 40th day after heading) and mapping QTLs associated with VG tolerance using the recombinant inbred lines (M/G RILs) from a cross between Milyang 23 (japonica/indica) and Gihobyeo (japonica). The VG rates of Milyang 23 and Gihobyeo were 0.0 and 7.0%, respectively. The averaged VG rate of 162 M/G RILs was 7.7%, and their range was from 0.0 to 50.9%. Of the 162 RILs, 144 lines were tolerant less than 10%, and 18 lines were susceptible more than 10%. Using the M/G RIL Map, three QTLs associated with the viviparous trait were detected on chromosome 2 (qVG 2-1 and qVG 2-2) and 8 (qVG 8). qVG 2-1 was linked to RM 32D and RZ 166, and had LOD score of 2.97. qVG 2-2 was tightly linked to E13M59.119-Pl and E13M59.M003-P2, and showed higher LOD score of 3.41. qVG 8 was linked to RM33 and TCT116, and had LOD score of 2.67. The total phenotypic variance explained by the three QTLs was about 24.4% of the total variance in the population. The detection of new QTLs associated with VG tolerance will provide important informations for the seed dormancy, low temperature germination, or comparative genetics.

• Journal of Crop Science and Biotechnology
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• v.11 no.4
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• pp.243-248
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• 2008

The bean bug Riptortus clavatus Thunberg (Heteroptera: Alydidae) is an important pest, causing serious yield loss in soybean. But the information on mechanism of resistance to R. clavatus is limited. The objective of this study was to identify QTLs for R. clavatus resistance using simple sequence repeat (SSR) markers in a soybean population of recombinant inbred lines (RILs) developed from the cross PI 171451 ${\times}$ Hwaeomputkong. A genetic map from this population was constructed with a total of 136 SSR markers covering 1073.9 cM on 20 linkage groups (LGs). With 126 $F_5$ RILs, two independent QTLs for resistance to R. clavatus were mapped on LGs B1 and C2. The amount of phenotypic variation explained by these QTLs ranged from 12 to 16%. PI 171451 showed an escape response to R. clavatus. Under feeding conditions, 14.4% of RILs showed greater resistance to R. clavatus than the resistant parent. The resistance to R. clavatus in soybean from PI 171451 was incomplete and quantitatively inherited and the QTLs for resistance to R. clavatus detected in the RIL population were not significantly affected by epistatic interactions.

• Korean Journal of Plant Resources
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• v.33 no.6
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• pp.615-623
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• 2020

Brassica rapa is one of the most valuable vegetable crops worldwide. Cultivated varieties of B. rapa exhibit diverse developmental and morphological appearances, which includes important vegetables, oilseeds, and fodder crops. In this study, various phenotypes of recombinant inbred lines (RILs) of B. rapa were investigated, including their responses to five different pathogenic Botrytis cinerea isolates, responses to aphid and thrips during flowering stages, days to flowering, and plant heights. Responses of 113 RILs to five different B. cinerea isolates showed variations, suggesting that genetic factors controlling resistance or tolerance against each isolate were dependent on isolate/genotype pairs. Correlation analysis was performed to understand the nature of genetic factors and the relationship among these phenotypes. Although high levels of correlation were not detected between phenotypes assessed in this study, statistically significant correlation was detected for several combinations. Significant positive correlations were found for different B. cinerea isolates, supporting that certain levels of commonality could exist in genetic components controlling resistance against different B. cinerea isolates. Based on correlation analysis using numbers of insects counted on plants, it was speculated that genetic factors responsible for aphid tolerance or repellence might be also involved in the response against thrips. Relationship between vegetative growth and tolerance against B. cinereal or insects is rather more complicated. However, it was observed that shorter plants appeared to have a certain level of tolerance or repellence against both aphids and thrips. Data presented in this study could be used to assist further genetic studies and breeding efforts to obtain Botritis and insect resistance for B. rapa.

• Journal of The Korean Society of Grassland and Forage Science
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• v.37 no.3
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• pp.242-247
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• 2017

Humic acid (HA) is a complex organic matter found in the environments, especially in grassland soils with a high density. The bioactivity of HA to promote plant growth depends largely on its extraction sources. The quality-control of HA and the quality improvements via an artificial synthesis are thus challenging. We recently reported that a polymeric product from fungal laccase-mediated oxidation of catechol and vanillic acid (CAVA) displays a HA-like activity to enhance seed germination and salt stress tolerance in a model plant, Arabidopsis. Here, we examined whether HA or CAVA enhances the growth of Italian ryegrass seedling. Height and fresh weight of the plant with foliar application of HA or CAVA were bigger than those with only water. Interestingly, enhanced root developments were also observed in spite of the foliar treatments of HA or CAVA. Finally, we proved that HA or CAVA promotes the regrowth of Italian ryegrass after cutting. Collectively, CAVA acts as a HA mimic in Italian ryegrass cultivation, and both as a biostimulant enhanced the early growth and regrowth after cutting of Italian ryegrass, which could improve the productivity of forage crops.

• Journal of The Korean Society of Grassland and Forage Science
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• v.37 no.3
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• pp.248-253
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• 2017

Humic acid (HA) is known to consist of various kinds of polymeric organics, their detailed structures can vary depend on sample sources such as organic manure, composts, peat, and lignite brown coal, and largely exists in grassland soils. HA possesses diverse positive effects that not only increase plant growth but also improve soil fertility. Recently, we have manufactured a co-polymeric product of catechol and vanillic acid (CAVA) synthesized artificially, and found that CAVA as a HA mimic increases seed germination and salt tolerance in Arabidopsis. In this study, we examined whether HA or CAVA affects to seedling growth in alfalfa. Foliar application of HA or CAVA increased alfalfa seedling growth including aerial and in root parts. HA or CAVA dramatically enhanced size of leaf and root, whereas HA significantly displayed higher bioactivity than CAVA. Taken together, CAVA acts like as a HA mimic in alfalfa that could apply as an alternation supplement to enhance plant growth and productivity.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.222-222
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• 2022

Improving the taste of rice in the breeding process is one of the important goals. However, it takes a lot of time and effort to select lines with good grain quality. MAS related to rice quality can help quickly and accurately select the elite lines in breeding programs. QTL qTV9, derived from Wandoaengmi 6, has been reported as a marker associated with improved glossiness of rice (Park et al., 2019). To confirm the function of QTL qTV9, 186 RILs derived from Hwayeong/Wandoaengmi6 were cultivated on ordinary planting cultivation for five years. The average DTH of Hwayeong and Wandoaengmi 6 was not significant at 99 and 97 days, respectively, but the averages of TV (toyo value) were 72.6 and 86.0, respectively. The DTH and TV of RIL vary from year to year. In 2017-2018, the average DTH was 98 days, which was significantly higher than the other three years. In 2018 and 2021, the average TV was 79.5 and 86.5, respectively, which were significantly higher than in other years. As a result of correlation analysis, DTH in the different years showed highly significant positive correlations (r = 0.71-0.92) from 0.71 to 0.92, whereas TV showed positive but weaker correlations (r = 0.42-0.71). The correlation between DTH and TV in each year was significant but weak (r = 0.25-0.64) and there was no correlation in 2017. The TV (77.6-88.7) of RILs with QTL qTV9 was significantly higher than that of RILs without qTV9 (72.6-84.9) for all five years. As a result of analyzing TV by DTH group, the TV of the lines with qTV9 in DTH groups (93-97) and (98-103) showed a significantly higher trend for all 5 years. And TV was not significant in DTH groups A, B, E, and F. This may have been influenced by factors such as insufficient populations between groups or differences in harvest timing. This study is expected to be used as data for improving the glossiness of cooked rice in breeding programs, and further study of the QTL qTV9 marker is required.

• Molecules and Cells
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• v.21 no.2
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• pp.192-196
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• 2006

Salt tolerance was evaluated at the young seedling stage of rice (Oryza sativa L.) using recombinant inbred lines (MG RILs) from a cross between Milyang 23 (japonica/indica) and Gihobyeo (japonica). 22 of 164 MG RILs were classified as tolerant with visual scores of 3.5-5.0 in 0.7% NaCl. Interval mapping of QTLs related to salt tolerance was conducted on the basis of the visual scores at the young seedling stage. Two QTLs, qST1 and qST3, conferring salt tolerance, were detected on chromosome 1 and 3, respectively, and the total phenotypic variance explained by the two QTLs was 36.9% in the MG RIL population. qST1 was the major QTL explaining 27.8% of the total phenotypic variation. qST1 was flanked by Est12~RZ569A, and qST3 was flanked by RG179~RZ596. The detection of new QTLs associated with salt tolerance will provide important information for the functional analysis of rice salt tolerance.