Bacillus velezensis K-9 as a Potential Biocontrol Agent for Managing Potato Scab.

Crop pathogen infections can lead to substantial economic losses, but biocontrol, an environmentally friendly approach, can be used to control infections. For the biological management of potato scab disease, we assessed the potential use of Bacillus velezensis as a biocontrol agent. B. velezensis K-9 inhibited up to 44.90% of the infection caused by Streptomyces scabies, the causative agent of potato scab. Treatment of the S. scabies-infected potato plants with B. velezensis K-9 resulted in a significant reduction in the depth of the disease lesions compared with the untreated infected potato plants. In a radish seedling test, the B. velezensis K-9 culture and cell-free filtrate significantly reduced (P < 0.05) potato scab disease symptoms, suggesting that the strain K-9 was able to reduce S. scabies pathogenesis on potatoes. In a field test, the disease and scab indexes for B. velezensis K-9 against potato scab were significantly different from the control. In 2021, the potato yield for the B. velezensis K-9-treated plants was 12.44% higher than that for the control plants. In 2022, the potato yield following B. velezensis K-9 treatment increased by 12.65% compared with the control. In conclusion, B. velezensis K-9 prevented potato scab and increased potato yield. Thus, B. velezensis K-9 substantially reduced the occurrence of potato scab and could be used as a potential biocontrol agent for the management of potato scab.

Effect of BBM gene on callus growth and ginsenoside content in Panax quinquefolius / 中国中药杂志

Baby Boom(BBM) gene is a key regulatory factor in embryonic development and regeneration, cell proliferation, callus growth, and differentiation promotion. Since the genetic transformation system of Panax quinquefolius is unstable with low efficiency and long period, this study attempted to transfer BBM gene of Zea mays to P. quinquefolius callus by gene gunship to investigate its effect on the callus growth and ginsenoside content, laying a foundation for establishing efficient genetic transformation system of P. quinquefolius. Four transgenic callus of P. quinquefolius with different transformation events were obtained by screening for glufosinate ammonium resistance and molecular identification by PCR. The growth state and growth rate of wild-type and transgenic callus were compared in the same growth period. The content of ginsenoside in transgenic callus was determined by ultra-high performance liquid chromatography-triple quadrupole mass spectrometry(UPLC-MS/MS). The results showed that transgenic callus growth rate was significantly higher than that of wild-type callus. In addition, the content of ginsenoside Rb_1, Rg_1, Ro, and Re was significantly higher than that in wild-type callus. The paper preliminarily proved the function of BBM gene in promoting growth rate and increasing ginsenoside content, which provided a scientific basis to establish a stable and efficient genetic transformation system for Panax plants in the future.

Isolation and identification of an endophytic bacteria Bacillus sp. K-9 exhibiting biocontrol activity against potato common scab.

Potato scab is an important soil-borne disease that can significantly reduce the quality and economic value of potatoes. The purpose of this study was to isolate, screen and identify endophytic bacteria that have antagonistic and control effects on potato scab disease, and to determine the control effect and yield traits of the selected strains on potato scab disease in field conditions. A bacterial strain K-9 was isolated from the junction between scab spot and healthy epidermis of potato tuber. The K-9 strain was identified as Bacillus sp. through morphological, physiological and biochemical characterization, and 16S rDNA and gyrB gene sequence analysis. The diameter of the inhibition zone of strain K-9 against Streptomyces scabies on the YME plate was 3.82 cm. The K-9 strain could inhibit eight types of crop pathogens, with the highest inhibition rate (70.39%) against another soil-borne potato disease (potato black scurf). In the field test, the control effect of K-9 strain against potato scab was not significantly different from that of mixed bacteria or chemical agents, but the disease index and the scab index in the K-9 treatment were significantly lower than in the control. The potato yield in the K-9 treatment was 12.44% higher than the control. In summary, the K-9 strain can prevent not only potato scab, but also increase potato yield. Therefore, the endophytic bacterial K-9 strain may be a potential biological control agent.

Effects of nitrogen and phosphorus addition on growth and leaf nitrogen metabolism of alfalfa in alkaline soil in Yinchuan Plain of Hetao Basin.

Alkaline soil is widely distributed in China. Its rational utilization is an effective measure to solve land shortage and improve the environment. Alfalfa is characterized by strong salt and alkali tolerance and high yield and protein content. Nitrogen (N) and phosphorus (P) are the main nutrients for plant growth, and N metabolism is one of the primary forms of plant metabolism, which plays a vital role in quality and yield formation. The exploration of the effect of N and P on N metabolism and alfalfa growth will provide a theoretical basis for scientific fertilization for alfalfa in the alkaline soil of the Yinchuan Plain of the Hetao Basin. Therefore, a 2-year experiment of N and P addition was conducted. Six treatments were set up with a randomized block design, including without N (WN), medium N (MN), high N (HN), without P (WP), medium P (MP), and high P (HP). It was found that the MN and MP treatments increased plant height, stem diameter, stem/leaf, dry/fresh, and dry matter of alfalfa. The HN and HP treatments inhibited alfalfa biomass formation. The MN and MP treatments increased key products and enzymes of leaf N metabolism of alfalfa and promoted activities of leaf nitrate reductase (NR), glutamine synthase (GS), glutamate synthase (GOGAT), glutamic-oxalacetic transaminase (GOT), and glutamic-pyruvate transaminase (GPT), and inhibited activities of leaf protease of alfalfa. The MN and MP treatments increased contents of leaf N, P, ammonium nitrogen (NH4 +-N), nitrate nitrogen (NO3 --N), total chlorophyll, and protein and reduced leaf chlorophyll a/b and amino acid, results after HN and HP treatments were opposite. The correlation among leaf P, N, NO3 --N, amino acid, and protein reached significant levels (P < 0.01). It is suggested that MN and MP treatments can improve the yield and quality of alfalfa by increasing key products and enzymes of N metabolism and can be adopted to promote alfalfa production in the alkaline soil of the Yinchuan Plain of the Hetao Basin.

Cardiac electrophysiological differences between Kunming and C57BL6/J mice / 中国医学科学杂志(英文版)

<p><b>OBJECTIVE</b>To investigate the alterations of cardiac electrophysiological properties and substantial mechanism and find the stable arrhythmia mouse model in Kunming (KM) and C57BL6/J (C57) mice.</p><p><b>METHODS</b>Electrocardiogram recordings were used to analyze the QT interval in vivo, and mono- phasic action potential of right and left ventricular epicardium was recorded to elicit changes of action potential duration (APD) in conventional and programmed electrical stimulation (PES). Transient outward potassium current (Ito) was recorded via whole-cell patch-clamp technique in single right and left epicardial myocytes.</p><p><b>RESULTS</b>QT interval was prolonged in KM mice relative to C57 mice (62.51±4.47 ms vs. 52.59±4.85 ms, P<0.05) The APD at 50% repolarization of the left ventricular epicardium (18.60±0.91 ms vs. 12.90±0.35 ms), and APDs at 50% (17.31±6.05 ms vs. 12.00±3.24 ms) and 70% repolarization (36.13±5.32 ms vs. 21.95±8.06 ms) of the right ventricular epicardium in KM mice were more sensitive to PES-induced ventricular tachycardia (25%, 3 of 12 hearts), and especially to Burst-induced ventricular tachycardia (50%, 6 of 12 hearts)compared with C57 mice, which were 20% (2 of 10 hearts) and 30% (3 of 10 hearts) respectively. Ito densities both in the left and right ventricular epicardial myocytes from KM mice were significantly decreased compared with C57 mice, respectively (all P<0.01).</p><p><b>CONCLUSION</b>Our data showed that KM mice with the prolonged QT interval and APD are vulnerabilities to ventricular arrhythmia, which are attributed to lower Ito densities in ventricular myocytes obtained from KM mice than that from C57 mice.</p>

Effect of zhigancao decoction containing serum on transient outward potassium current in isolated single ventricular myocyte of rabbits / 中国中西医结合杂志

<p><b>OBJECTIVE</b>To investigate the effect of Zhigancao Decoction (ZD) containing serum on transient outward potassium current (I(to)) in isolated single ventricular myocyte of rabbits.</p><p><b>METHODS</b>Single rabbit ventricular myocytes were isolated and divided into 6 groups, the normal group, the non-drug-containing serum group, and the ZD groups, they were treated with normal extracellular fluid alone or with ZD containing serum recording technique was used to observe the changes of I(to).</p><p><b>RESULTS</b>After treated with 5%, 10%, 20% and 40% ZD containing serum, the I(to) was inhibited and its peak value dropped from (16.1 +/- 1.4) PA/PF to (13.9 +/-1.5) PA/PF, (11.8 +/- 1.9) PA/PF, (8.3 +/- 1.5) PA/PF and (8.2 +/- 1.2) PA/PF respectively, and the effect could be eliminated by elution.</p><p><b>CONCLUSION</b>ZD containing serum could inhibit the I(to) in isolated ventricular myocytes of rabbits in a concentration-dependent manner, which may be the mechanism of antiarrhythmic action of ZI).</p>

Effect of Qianjin Fubao on changes of behavior and estradiol level in chronic stress model rats / 中国中药杂志

<p><b>OBJECTIVE</b>To investigate the effect of Qianjin Fubao (QJFB) on behavior and estradiol level in femal chronic stress model rats.</p><p><b>METHOD</b>Twenty four female Wistar rats (2 month old) were evenly randomized into normal control, animal model and QJFB (0.7 g x kg(-1) x d(-1)) group. The QIFB group and the stress group were exposed to a chronic unpredictable stress for 21 days. Rats of the QJFB group received perfusion of Qianjin Fubao, and rats of stress and control group were perfused with normal saline. The behavior of three groups were determined with the method of Open-field before and after right stress respectively. Serum level of estradiol was detected with radioim munoassay.</p><p><b>RESULT</b>The behavioral score and the serum level of estradiol of the stressed group were significantly lower than those of the control group after stress (P < 0.05). There were no significant differences of behavioral score and the serum level of estradiol between QJFB group and control group.</p><p><b>CONCLUSION</b>The chronic unpredictable stress can induce the stressful change of behavior, and QJFB may recover the rats'abnormal behavior and improve the serum level of estradiol. QJFB may have protective effect on stress.</p>