Integrated Analysis of miRNAs Associated With Sugarcane Responses to Low-Potassium Stress

Sugarcane is among the most important global crops and a key bioenergy source. Sugarcane production is restricted by limited levels of available soil potassium (K+). The ability of plants to respond to stressors can be regulated by a range of microRNAs (miRNAs). However, there have been few studies regarding the roles of miRNAs in the regulation of sugarcane responses to K+-deficiency. To understand how these non-coding RNAs may influence sugarcane responses to low-K+ stress, we conducted expression profiling of miRNAs in sugarcane roots under low-K+ conditions via high-throughput sequencing. This approach led to the identification of 324 and 42 known and novel miRNAs, respectively, of which 36 were found to be differentially expressed miRNAs (DEMs) under low-K+ conditions. These results also suggested that miR156-x/z and miR171-x are involved in these responses as potential regulators of lateral root formation and the ethylene signaling pathway, respectively. A total of 705 putative targets of these DEMs were further identified through bioinformatics predictions and degradome analyses, and GO and KEGG enrichment analyses revealed these target mRNAs to be enriched for catalytic activity, binding functions, metabolic processes, plant hormone signal transduction, and mitogen-activated protein kinase (MAPK) signaling. In summary, these data provide an overview of the roles of miRNAs in the regulation of sugarcane response to low-K+ conditions.

Effect of forecrop on yield of spring durum wheat and soil potassium in chernozems of southern steppe zone in Southern Urals during long-term research

The goal of the study was to determine the infl nce of forecrops on spring durum wheat productivity and content of soil potassium in monoculture, double-cropping and six-year crop rotation at two types of nutrient statuses. The information obtained as a result of long-term experiments is of great interest, since systematic determination of nutrient elements in soil gives a correct assessment of the effect of the longterm use of fertilizers on soil fertility. Content of available forms of potassium in soil under spring durum wheat depending on different forecrops and nutrient statuses was studied. The best forecrops for durum wheat in 31-year experiments were black, soil-protecting and green fallows. The yield of durum wheat after black fallow was 1.20 t/ha under fertilization and 1.27 t/ha without using fertilizers. Vegetative mass of cropped fallow ploughed into soil and use of mineral fertilizers led to an increase in content of soil potassium. The use of mineral fertilizers has a positive effect on yield of durum wheat; the yield increase was 0.10 t/ha after soil protecting fallow, 0.11 t/ha after common wheat and 0.13 t/ha after winter rye. Content of soil potassium was higher in six-year crop rotation and it increased durum wheat productivity compared to double-cropping and monoculture.

Long-term straw returning improve soil K balance and potassium supplying ability under rice and wheat cultivation

The aims of the present study were to provide scientific bases for rational use of crop straw to substitute chemical potassium (K) input. The effects of potassium fertilization and straw incorporation on soil K balance and K supplying in a long-term (14 years) field experiment. Five treatments were examined: (1) no fertilization (CK); (2) mineral fertilizing (NPK); (3) straw 6000 kg h m−2 (S); (4) NPK with straw 3000 kg h m−2 (NPK1/2S); and (5) NPK with straw 6000 kg h m−2 (NPKS). K composition, K balance and quantity-intensity (Q/I) relationship were studied. Under no fertilization or low straw returned conditions, soil K was unbalanced and deficienct seriously. Straw return at 6000 kg h m−2 per season with fertilization improved the soil potassium supply and K balance. Long-term K surplus (4 or 5 years), compared with NPK, the NPKS significantly increased non-special K adsorption (Knsa) and non-exchangeable K (Kne) by 5.7–11.2 mg kg−1 and 65.7–128.1 mg kg−1, respectively. Q/I relationship showed cropping without straw K or without fertilizer K resulted in lower quantity (nonspecifically and specifically held K i.e. – ∆K0 and Kx) and intensity (equilibrium activity ratio i.e. CR0K) of K in tested soils. K-fertilization with straw maintain higher exchangeable K (EK0) and a higher difference between EK0 and minimum exchangeable K(EKmin), and would help to prevent depletion in non-exchangeable pool of soil K under intensive cropping. Additionally, The straw return mainly decreased potential buffering capacity for exchangeable pool (PBCKn), 43.92–48.22% of added K in soil might be converted to exchangeable pool while it was 25.67–29.19% be converted to non-exchangeable pool. The contribution of exchangeable K towards plant K uptake would be higher in the soil with straw than the soil without straw and the non-exchangeable K would be the long-term fixed K as a supplement to the potassium pool. K fertilizer with 6000 kg h m−2 straw return in each crop season increased soil available K and slowly available K. The findings underlined importance of the straw return and contribution for sustain K supplying ability of soils.

Potassium mobilization and plant growth promotion by soil bacteria isolated from different agroclimatic zones of Odisha, India

<p class="042abstractstekst"><span lang="EN-US">Potassium is essential for plant metabolism; improves immunity to stress and increase crop productivity. Soil contains insoluble form of potassium, which is unavailable for plant absorption. Potash mobilizing bacteria (KMB) solubilise complex potassium and make it available to plant. KMB with plant growth promoting (PGP) traits could enhance growth and crop productivity. Here we attempt to screen KMBs with PGP traits from different agroclimatic zones of Odisha and study dynamics of potassium in soil. Isolation of KMB and determination of PGP traits was performed with standard protocols. Pot culture experiment was aimed to study their effect on sunflower crop. Available soil potassium was quantified using inductively coupled plasma-optical emission spectrometry (ICP-OES). Thirty KMBs were isolated from different agro-climatic zones of Odisha, out of which 6 isolates exhibited maximum PGP traits. Moreover, after adding inoculums the available soil potassium decreased over 0 to 30 days as compared to control, with increase in shoot length. T7 (consortium) reported maximum (144 %) increase in shoot length. Available soil potassium content decreased with increase in time. A maximum decrease was reported in T7 (26.31 %), suggesting potassium accumulation by plant.</span></p>

Potassium mobilization and plant growth promotion by soil bacteria isolated from different agroclimatic zones of Odisha, India

<p class="042abstractstekst"><span lang="EN-US">Potassium is essential for plant metabolism; improves immunity to stress and increase crop productivity. Soil contains insoluble form of potassium, which is unavailable for plant absorption. Potash mobilizing bacteria (KMB) solubilise complex potassium and make it available to plant. KMB with plant growth promoting (PGP) traits could enhance growth and crop productivity. Here we attempt to screen KMBs with PGP traits from different agroclimatic zones of Odisha and study dynamics of potassium in soil. Isolation of KMB and determination of PGP traits was performed with standard protocols. Pot culture experiment was aimed to study their effect on sunflower crop. Available soil potassium was quantified using inductively coupled plasma-optical emission spectrometry (ICP-OES). Thirty KMBs were isolated from different agro-climatic zones of Odisha, out of which 6 isolates exhibited maximum PGP traits. Moreover, after adding inoculums the available soil potassium decreased over 0 to 30 days as compared to control, with increase in shoot length. T7 (consortium) reported maximum (144 %) increase in shoot length. Available soil potassium content decreased with increase in time. A maximum decrease was reported in T7 (26.31 %), suggesting potassium accumulation by plant.</span></p>