Management of the soybean cyst nematode <i>Heterodera glycines</i> with combinations of different rhizobacterial strains on soybean

<div><p>Soybean cyst nematode (SCN) is the most damaging soybean pest worldwide. To improve soybean resistance to SCN, we employed a soybean seed-coating strategy through combination of three rhizobacterial strains, including <i>Bacillus simple</i>, <i>B</i>. <i>megaterium</i> and <i>Sinarhizobium fredii</i> at various ratios. We found seed coating by such rhizobacterial strains at a ratio of 3:1:1 (thereafter called SN101) produced the highest germination rate and the mortality of J2 of nematodes. Then, the role of soybean seed coating by SN101 in nematode control was evaluated under both greenhouse and two field conditions in Northeast China in 2013 and 2014. Our results showed that SN101 treatment greatly reduced SCN reproduction and significantly promoted plant growth and yield production in both greenhouse and field trials, suggesting that SN101 is a promising seed-coating agent that may be used as an alternative bio-nematicide for controlling SCN in soybean fields. Our findings also demonstrate that combination of multiple rhizobacterial strains needs to be considered in the seed coating for better management of plant nematodes.</p></div

Effects of SN101 seed coating on soybean height and root length under greenhouse condition.

<p>Plants were treated with biocontrol seed coating-sn101, chemical seed coating-BFA and uncoated-CK. The plant height and root length was measured after nematode inoculation 30 days. The data in the figure are mean ± SE and means on the same column followed by different letters indicate significant differences based on a LSD test (<i>P</i> ≤ 0.05, n = 125).</p

Effects of SN101 seed coating on soybean height and root length under filed conditions in 2013 and 2014.

<p>Plants were treated with biocontrol seed coating-sn101, chemical seed coating-BFA and uncoated-CK. The seedling plant height, mature plant height and seedling root length was measured in seedling (after planted 30–35 days) and mature (about after planted 150 days). The data in the figure are mean ± SE and means on the same column followed by different letters indicate significant differences based on a LSD test (<i>P</i> ≤ 0.05, n = 125). <b>A.</b> seedling plant height, <b>B.</b> mature plant height, <b>C.</b> seedling root length.</p

Analysis of variance of three factors (years, sites and treatments).

<p>Analysis of variance of three factors (years, sites and treatments).</p

Effect of five SN101 biocontrol agents on mortality of second-stage juveniles of <i>Heterodera glycines</i>.

<p>Effect of five SN101 biocontrol agents on mortality of second-stage juveniles of <i>Heterodera glycines</i>.</p

SN101 seed coating inhibited SCN infection under soybean filed conditions in 2013 and 2014.

<p>Plants were treated with biocontrol seed coating-SN101, chemical seed coating-BFA and uncoated-CK. The number of juveniles in roots, cysts in soil and in roots, and eggs per cyst was measured after planted 30–35 days. The data in the figure are mean ± SE and means on the same column followed by different letters indicate significant differences based on a LSD test (<i>P</i> ≤ 0.05). <b>A.</b> the number of cysts per root system (n = 125), <b>B.</b> the number of cysts per 100 g of rhizosphere soil (n = 25), <b>C.</b> the number of juveniles per gram of root (n = 125), <b>D.</b> the number of eggs per cyst (n = 25).</p

Manipulation of the Topological Ferromagnetic State in a Weyl Semimetal by Spin–Orbit Torque

Magnetic Weyl semimetals (MWSMs) exhibit unconventional transport phenomena, such as large anomalous Hall (and Nernst) effects, which are absent in spatial inversion asymmetry WSMs. Compared with its nonmagnetic counterpart, the magnetic state of a MWSM provides an alternative way for the modulation of topology. Spin–orbit torque (SOT), as an effective means of electrically controlling the magnetic states of ferromagnets, may be used to manipulate the topological magnetic states of MWSMs. Here we confirm the MWSM state of high-quality Co2MnGa film by systematically investigating the transport measurements and demonstrating that the magnetization and topology of Co2MnGa can be electrically manipulated. The electrical and magnetic optical measurements further reveal that the current-induced SOT switches the topological magnetic state in a 180-degree manner by applying positive/negative current pulses and in a 90-degree manner by alternately applying two orthogonal current pulses. This work opens up more opportunities for spintronic applications based on topological materials

Effect of SN101 on soybean yields under field conditions in Kangping and Daqing in 2013 and 2014 (<i>P</i> ≤ 0.05).

<p>Effect of SN101 on soybean yields under field conditions in Kangping and Daqing in 2013 and 2014 (<i>P</i> ≤ 0.05).</p

Effect of biocontrol agents on soybean seed germination and seedling vigor (<i>P</i> ≤ 0.05).

<p>Effect of biocontrol agents on soybean seed germination and seedling vigor (<i>P</i> ≤ 0.05).</p

Effect of SN101 on final yields of soybeans under field conditions in Heihe from 2012 to 2015 and in Jiusan from 2012 to 2016.

<p>Effect of SN101 on final yields of soybeans under field conditions in Heihe from 2012 to 2015 and in Jiusan from 2012 to 2016.</p