Effects of wild or mutated inoculants on rye silage and its rumen fermentation indices

Objective

This study was conducted to confirm the effects of new inoculants producing-antifungal or esterase substances on rye silage and its rumen fermentation indices by comparing wild with mutated types.

Methods

Rye harvested at dough stage was ensiled into 3 L mini bucket silo (1 kg) for 90 d in triplicate following: distilled water at 20 μL/g (CON); Lactobacillus brevis 100D8 (AT) and its inactivation of antifungal genes (AT-m) at 1.2×10⁵ cfu/g, respectively; and Leuconostoc holzapfelii 5H4 (FD) and its inactivation of esterase genes (FD-est) at 1.0×10⁵ cfu/g, respectively. After silo opened, silage was sub-sampled for the analysis of ensiling quality and its rumen fermentation indices.

Results

Among the wild type inoculants (CON vs AT vs FD), FD inoculant had higher (p<0.05) in vitro digestibilities of dry matter and neutral detergent fiber, the total degradable fraction, and total volatile fatty acid in rumen, while AT inoculant had higher (p<0.05) lactate, acetate, and lactic acid bacteria in silage. Silage pH and the potentially degradable fraction in rumen increased (p<0.05) by inactivation of antifungal activity (AT vs AT-m), but lactate, acetate, and lactic acid bacteria of silage decreased (p<0.05). In silage, acetate increased (p< 0.05) by inactivation of esterase activity (FD vs FD-est) with decreases (p<0.05) of pH, ammonia-N, lactate, and yeast. Moreover, inactivation of esterase activity clearly decreased (p<0.05) in vitro digestibilities of dry matter and neutral detergent fiber, the total degradable fraction, and total volatile fatty acid in the rumen.

Conclusion

This study concluded that FD inoculant confirmed esterase activity on rye silage harvested at dough stage, while AT inoculant could not be confirmed with antifungal activity due to the absence of mold in all silages.

Screening and investigation Lactobacillius spp. to improve Secale cereale silage quality

Silage is a high-moisture-content forage that is used to feed livestock. Using silage as feed is economically feasible and suitable for cattle management. Secale cereale is considered as a high-quality forage plant. After the heading stage the biomass of S. cereale increases by up to 30%; however, lignification in the cell wall causes low fermentation efficiency and coefficient digestibility, and it may also be contaminated by mycotoxin-producing fungi and can impair the quality of the silage. Therefore, the aim of this study was to screen beneficial Lactobacillius spp. for S. cereale silage to reduce fungi contamination and to increase fibrinolytic ability in the silage. Up to 100 days fermentation period and total 180 lactic acid bacteria were isolated and only a single isolate, R4-26, showed strong acidification ability and antifungal activities against mycotoxin-producing fungus. According to quantitative RT-PCR results, the mycotoxin-producing fungal contamination was significantly reduced in the S. cereale silage containing the R4-26 isolate. In enzymatic assays, only a single isolate, R48-27 demonstrated cellulase, xylanase, chitinase and esterase activities. In conclusion, the beneficial Lactobacillius spp. strains have the ability to reduce mycotoxigenic fungi contamination and increase fibrinolytic activity to improve quality of the S. cereale silage.

Complete genome sequence and functional study of the fibrinolytic enzyme-producing bacterium Leuconostoc holzapfelii 5H4, a silage probiotic

To process silage, rye is usually removed before the heading stage but the rye biomass increased up to 30% after the heading stage. However, after the heading stage, lignification rapidly accelerated and it resulted in a poor NDF digestibility problem. This has led to a demand for a strong fibrinolytic enzyme-producing probiotic for rye silage. The Gram-positive Leuconostoc holzapfelii 5H4 was selected as a fibrinolytic enzyme-producing probiotic to overcome lignification of rye silage. The L. holzapfelii 5H4 has a relatively small circular chromosome (1,885,398 bp), but the strain has one cellulase, two xylanase, and five esterase in its genome sequence. All fibrinolytic enzyme genes were relatively highly expressed compared to housekeeping genes, and this was confirmed by qRT-PCR. In this study, we report the complete genome sequence of the bacterium so that fibrinolytic enzyme production and its fibrinolytic activity mechanism are better understood.

Effects of Different Cutting Height on Nutritional Quality of Whole Crop Barley Silage and Feed Value on Hanwoo Heifers

The present study evaluated the effects of different cutting height on nutritive value, fermentation quality, in vitro and in vivo digestibility of whole crop barley silage. Whole crop barley forage (Yuyeon hybrid) was harvested at height of 5, 10, and 15 cm from the ground level. Each cutting height was rolled to make round bale and ensiled for 100 days. After 100 days of ensiling, pH of silage was lower (p<0.05) in 5 cm, but no difference between 10 and 15 cm of cutting height. The content of lactate and lactate to acetate ratio were increased (p<0.05) in 5 cm of cutting height, whereas the acetate content was higher (p<0.05) in 10 and 15 cm than that of 5 cm cutting height. Aerobic stability was greater (p<0.05) in silages of 10 and 15 cm of cutting height. Three total mixed rations (TMR) were formulated with silages from the three different cutting heights (TMR5, TMR10, and TMR15) incorporated as forage at 70:30 ratio with concentrate (dry matter [DM] basis). In vitro dry matter digestibility was higher (p<0.05) in the TMR5 and TMR10 than that in TMR15, whereas in vitro neutral detergent fiber digestibility was higher (p<0.05) in the TMR10 and TMR15 than that in TMR5. Concentration of NH3-N was highest (p<0.05) in the TMR10 followed by TMR15 and TMR5. Total volatile fatty acid was decreased (p<0.05) with increased cutting height. The digestibility of DM and neutral detergent fiber were highest (p<0.05) in TMR15, than those in TMR5 and TMR10, whereas acid detergent fiber digestibility was higher (p<0.05) in TMR5 than that in TMR10. The results showed that increasing cutting height, at least up to 10 to 15 cm, of whole crop barley forage at harvest (Yuyeon) may be beneficial for making silage for TMR formulation and increasing digestibility of DM and NDF.

Genome dissection of traits related to domestication in azuki bean (Vigna angularis) and comparison with other warm-season legumes

BACKGROUND

The objective of this study was to dissect into quantitative trait loci (QTLs) the large morphological and physiological differences between cultivated azuki bean (Vigna angularis) and a wild relative and to infer the commonalities of the QTLs for domestication-related traits across the Asian Vigna and with other warm-season legumes.

METHODS

Two linkage maps, for the BC(1)F(1) and F(2) populations, respectively, from the same cross between azuki bean and V. nepalensis were developed. Using these linkage maps QTLs for 33 domestication-related traits were analysed and mapped. The location of mapped QTLs was compared with locations of similar QTLs in other warm-season legumes.

KEY RESULTS

QTLs were detected for seed-, pod-, stem- and leaf-related traits. Most traits were controlled by between two and nine QTLs but several traits, such as pod dehiscence, were controlled by single genes. QTLs for domestication-related traits were restricted to particular regions of the azuki bean genome, especially linkage groups 1, 2, 4, 7 and 9. Linkage groups 1 and 2 had QTLs for a suite of traits including pod size, germination, seed size and lower stem length. QTLs on linkage groups 7 and 9 were associated with upper stem length, maximum leaf size and pod and seed size. Pleiotropy or close linkage of genes for domestication-related traits is suggested in these regions. While some QTLs are common to azuki bean and other warm-season legumes, many are recorded for the first time in azuki bean.

CONCLUSIONS

QTLs for a large number of domestication-related traits have been mapped for the first time in azuki bean. QTLs with unexpected effect and new QTLs for traits such as seed size have been found. The results provide a foundation that will be useful for improvement of azuki bean and related legumes.

A genetic linkage map for azuki bean [Vigna angularis (Willd.) Ohwi & Ohashi]

To make progress in genome analysis of azuki bean (Vigna angularis) a genetic linkage map was constructed from a backcross population of (V. nepalensis x V. angularis) x V.angularis consisting of 187 individuals. A total of 486 markers-205 simple sequence repeats (SSRs), 187 amplified fragment length polymorphisms (AFLPs) and 94 restriction fragment length polymorphisms (RFLPs) -were mapped onto 11 linkage groups corresponding to the haploid chromosome number of azuki bean. This map spans a total length of 832.1 cM with an average marker distance of 1.85 cM and is the most saturated map for a Vigna species to date. In addition, RFLP markers from other legumes facilitated finding several orthologous linkage groups based on previously published RFLP linkage maps. Most SSR primers that have been developed from SSR-enriched libraries detected a single locus. The SSR loci identified are distributed throughout the azuki bean genome. This moderately dense linkage map equipped with many SSR markers will be useful for mapping a range of useful traits such as those related to domestication and stress resistance. The mapping population will be used to develop advanced backcross lines for high resolution QTL mapping of these traits.

The genetic diversity of the Vigna angularis complex in Asia

A selected set of accessions of components of the azuki bean (Vigna angularis) complex comprising 123 cultivated accessions and 23 wild or weedy accessions from Bhutan, China (including Taiwan), India, Japan, Korea, and Nepal was analyzed using amplified fragment length polymorphism (AFLP) methodology. Using 12 AFLP primer pairs, 580 unambiguous bands were generated, 313 (53.9%) of which were polymorphic among azuki bean accessions. All 580 bands were used to assess phenotypic (band) and genetic (nucleotide) diversity among the 146 azuki bean accessions. The results indicate five major groups of azuki bean germplasm primarily associated with geographic origin of accessions and their status: wild, weedy, or cultivated. These five groups are (i) Himalayan wild, (ii) Nepal-Bhutan cultivated, (iii) Chinese wild, (iv) Taiwan wild - Bhutan cultivated, and (v) northeast Asian accessions. Within the northeast Asian accessions, three subgroups are present. These consist of (v1) Japanese complex - Korean cultivated, (v2) Japanese cultivated, and (v3) Chinese cultivated accessions. The results suggest domestication of azuki bean occurred at least twice, once in the Himalayan region of southern Asia and once in northeast Asia. The remarkable diversity of azuki bean germplasm in the Himalayan region compared with other regions suggests this is a rich source of germplasm for plant breeding. The results suggest there are important gaps in the germplasm collections of azuki bean and its close relatives from various parts of Asia and that specific collecting missions for Vigna germplasm related to azuki bean in the highlands of subtropical Asia are needed.

Characterization of resistance to three bruchid species (Callosobruchus spp., Coleoptera, Bruchidae) in cultivated rice bean (Vigna umbellata)

Resistance of wild and cultivated rice bean (Vigna umbellata [Thunberg] Ohwi and Ohashi) to three bruchid species, Callosobruchus chinensis L., Callosobruchus maculatus F., and Callosobruchus analis F., was evaluated. All but three accessions of cultivated, and all wild rice bean accessions tested, exhibited complete resistance to all three bruchid species. Rice bean seeds with seed coat removed also showed complete resistance to the three bruchid species. Results indicate that physical attributes and/or chemical(s) present in the seed coat of rice bean are not the main factors responsible for resistance. Feeding tests were performed by using artificial beans prepared with varying proportions of rice bean (resistant) and azuki bean (susceptible) flour. Number of bruchid adults that emerged decreased, and larval developmental period (days) was extended, when artificial beans with an increasing proportion of rice bean flour were used. These tests revealed that a chemical compound(s) contained in the cotyledon of rice bean has an inhibitory effect on the growth of these bruchid species. The results also indicate that the chemical(s) in rice bean cotyledon is most effective against C. maculatus.

Genetic and linkage analysis of cleistogamy in soybean

Early maturing cultivars of soybean [Glycine max (L.) Merr.] native to the shores of the Sea of Okhotsk (Sakhalin and Kuril Islands) and eastern Hokkaido (northern Japan) have been used in breeding for chilling tolerance. These cultivars have a strong tendency to produce cleistogamous flowers throughout their blooming period. This study was conducted to determine the genetic basis of cleistogamy in an early maturing cultivar, Karafuto-1, introduced from Sakhalin. Genetic analysis was performed using F1 plants, the F2 population, and 50 F3 families produced by crossing between Karafuto-1 and a chasmogamous cultivar, Toyosuzu. F2 plants had chasmogamous flowers, indicating that chasmogamy was dominant to cleistogamy. Analysis of F2 populations and F3 families generated segregation data that was close to a two-gene model with epistatic interactions, although a portion of the pooled F3 data on the frequency of chasmogamous segregants from cleistogamous families significantly deviated from the model. The results suggested that a minimum of two genes with epistatic effects were involved in the genetic control of cleistogamy. Furthermore, cleistogamy was associated with early flowering in the F2 and F3 populations. A gene for cleistogamy was linked to one of the recessive genes responsible for insensitivity to incandescent long daylength.