Breeding a Soybean Cultivar Heinong 531 with Peking-Type Cyst Nematode Resistance, Enhanced Yield and High Seed-Oil Contents

Soybean cyst nematode (SCN) is a destructive threat to soybean production. It’s of economic importance to develop a new SCN-resistant soybean cultivar with high yield and other good agronomic traits. In this study, a yellow-seed-coated and yellow-hilum-pigmented cultivar Heinong 531 belonging to maturity group I was developed by a pedigree breeding method through a testcross between a female parental SCN-resistant soybean cultivar Pengdou 158 and a male parental line F1 (high-yield but SCN-susceptible Hefeng 55 x SCN-resistant Kangxian 12). Heinong 531 was evaluated for SCN resistance in both SCN-infested field and autoclaved soil inoculated with hatched second-stage juveniles of SCN HG Type 0. The results indicated that SCN development at all stages in Heinong 531 was suppressed and the female index was only 1.6-5.6%. Heinong 531 as well as Pengdou 158 and Kangxian 12 were identified to carry the Peking-type resistance with both rhg1-a GmSNAP18 and Rhg4 GmSHMT08 genes. In the two-year regional trials, the average yield of Heinong 531 reached 2805.0 Kg/ha and the one-year production trial demonstrated an average yield of 2751.5 Kg/ha with yield increase of over 12.0% when compared to the local cultivars. The average seed-fat (oil) contents of Heinong 531 reached up to 22.3%. The Peking-type SCN-resistant Heilong 531 cultivar with enhanced yield and high seed-oil contents was just released in China in June, 2021 with certified number of ‘Heishendou 20210004’. These good agronomic traits make Heinong 531 prospective in a wide extension to control SCN in the main soybean-producing areas of Northeast China.

Introducing Negatively Charged Residues on the Surface of Fetal Hemoglobin Improves Yields in Escherichia coli

Fetal hemoglobin (HbF) has been developed into an important alternative protein for oxygen therapeutics. Such applications require extensive amounts of proteins, which only can be achieved via recombinant means. However, the expression of vertebrate hemoglobins in heterologous hosts is far from trivial. There are several issues that need to be dealt with. These include, among others, the solubility of the globin chains, equimolar expression of the globin chains, and access to high levels of free heme. In this study, we examined the impact of introducing negative charges on the surface of HbF. Three different HbF mutants were examined, carrying four additional negative charges on the α-subunit (rHbFα4), two additional negative charges on the γ-subunit (rHbFγ2) or a combination of these (rHbFα4/γ2). The increase in negative surface charge in these HbF mutants required the development of an alternate initial capture step in the downstream purification procedures. For the rHbFα4 mutant, we achieved a significantly enhanced yield of purified HbF with no apparent adverse effects on Hb functionality. However, the presence of non-functional Hb portions in the rHbFγ2 and rHbFα4/γ2 samples reduced the yields significantly for those mutants and indicated an imbalanced expression/association of globin chains. Furthermore, the autoxidation studies indicated that the rHbFγ2 and rHbFα4/γ2 mutants also were less oxidatively stable than rHbFα4 and wt rHbF. The study further verified the need for an improved flask culture protocol by optimizing cultivation parameters to enable yield-improving qualities of surface-located mutations.