Soybean Cultivation and BBF in China

Abstract

China is the geographical origin of cultured soybeans and is where they have been cultivated for more than 5,000 years. Soybean is grown in nearly all provinces of China, the exceptions being Qinghai and the Tibetan Plateau. Based on climatic differences, China can be divided into five main geographical regions as regards soybean cultivation. As a complementary classification, Chinese soybean varieties have also been classified according to the sowing date; they were divided into winter-, spring-, summer-, and autumn-sowing varieties. In spite of the soybean acreage in China (9.4 million ha in 2001), which ranks fourth in the world, China has also become the largest soybean importer in the world. Although China has greatly improved soybean productivity in the last 20 years, its total production (or average seed yield) is still clearly lower than that reached in western countries. The symbiotic interaction, which soybean forms with different rhizobia, is a key factor in increasing soybean productivity in China within the context of agricultural sustainability. Research efforts in China have mainly concentrated on the identification and characterisation of biological material, both soybean accessions and rhizobial strains that effectively nodulate soybeans. As a result of this activity, a large collection of soybean germplasm is available and the existence of a broad spectrum of bacteria that nodulate soybeans (which we will collectively call "soybean-rhizobia") has been demonstrated.However, although soybean

Sinorhizobium fredii HH103 syrM inactivation affects the expression of a large number of genes, impairs nodulation with soybean and extends the host‐range to Lotus japonicus

“…Thus, whereas lack of the 'primary' modulator of the HH103 nod regulon (NodD1) fully impair symbiosis with all the legumes tested so far (Vinardell et al, 2004b;Acosta-Jurado et al, 2016b, 2019, the absence of 'secondary' modulators such as NolR, NodD2 or SyrM can have positive or negative effects depending on the host tested. Maybe, the fine-tuning modulation of HH103 symbiotic genes provided by these transcriptional regulators has evolved in order to improve symbiotic performance with soybean, a natural host of strain HH103 (both symbionts, bacterium and legume, are native to China; Ruiz-Sainz et al, 2005;Margaret et al, 2011;Temprano-Vera et al, 2018), even thought it could diminish (or abolish) the effectivity of this strain with other legumes. In other words, S. fredii HH103 can produce symbiotic signals adequate to nodulate (and induce ITs formation) with L. japonicus Gifu, but the presence of fine-tuning modulators of symbiotic genes such as NolR, NodD2 and SyrM prevents this interaction.…”

Bacterial Molecular Signals in the Sinorhizobium fredii-Soybean Symbiosis

“…Soybean is a crop plant of enormous economic and agronomic interest [ 4 ]. S. fredii strains are potentially valuable for their use as soybean inoculants since they are able to grow much faster than bradyrhizobia.…”

Interactive Effects of Nutrients and Bradyrhizobium japonicum on the Growth and Root Architecture of Soybean (Glycine max L.)

“…Merr.) is the most important source of oil and protein in many countries around the world (Ruiz-Sainz et al, 2005 ; Qin et al, 2011 ). Soybean requires an adequate amount of nutrients for optimal growth and development to maximize yield.…”