No abstract

Core Ideas SOC and AOC were higher in CT and RT treatments than RTO at 0 to 5, 5 to 10, and 10 to 20 cm. Lability, LI, and CMI in the CT treatment were higher than NT treatment at 0 to 5 and 10 to 20 cm. SOC stocks were significantly higher in NT at 0 to 5 cm than under the RTO treatment. SOC stocks were significantly higher in CT and RT at 5 to 10 and 10 to 20 cm than under RTO. Interactions between tillage and soil organic carbon (SOC) impact soil structure, soil quality, and the calculated soil carbon management index (CMI). However, the effects of different tillage and residue management systems on the dynamics of SOC remain unclear under double‐cropping rice (Oryza sativa L.). Therefore, the effects of soil tillage and incorporated residues on soil bulk density, SOC, soil active organic carbon (AOC), and the CMI were studied in a southern China double‐cropped rice system. The experiment included four tillage treatments: conventional tillage with residue incorporation (CT), rotary tillage with residue incorporation (RT), no tillage with residue retention (NT), and rotary tillage with residue removed as a control (RTO). The results indicated that soil bulk density increased under NT in the 0‐ to 20‐cm layer, SOC was higher under NT than that of other treatments, and SOC in the 5‐ to 20‐cm layer was higher under CT and RT than under NT and RTO. The greatest SOC and AOC contents were observed under CT at the 5‐ to 10‐cm and 10‐ to 20‐cm layers. The CMI was used to assess the soil quality change with different soil tillage practices. The application of residue combined with conventional tillage or rotary tillage was more effective for increasing soil carbon pool index (CPI) and CMI than was rotary tillage with the residue was removed. The CMI for the 0‐ to 10‐cm depth under RT and CT were higher (P < 0.05) than the NT treatment. Meanwhile, RT significantly enhanced the SOC stocks over the RTO treatment at three different depths. As a result, based on soil CMI and C storage, double‐cropping rice using a no‐tillage system where crop residues are not removed could increase SOC in the surface 5 cm.

No abstract

The genetic bases underlying esophageal tumorigenesis are poorly understood. Our previous studies have shown that coordinated deletion of the Smad4 and PTEN genes results in accelerated hair loss and skin tumor formation in mice. Herein, we exemplify that the concomitant inactivation of Smad4 and PTEN accelerates spontaneous forestomach carcinogenesis at complete penetrance during the first 2 months of age. All of the forestomach tumors were invasive squamous cell carcinomas (SCCs), which recapitulated the natural history and pathologic features of human esophageal SCCs. A small population of the SCC lesions was accompanied by adenocarcinomas at the adjacent submucosa region in the double mutant mice. The rapid progression of forestomach tumor formation in the Smad4 and PTEN double knockout mice corresponded to a dramatic increase in esophageal and forestomach epithelial proliferation. The decreased expression of p27, p21, and p16 together with the overexpression of cyclin D1 contributed cooperatively to the accelerated forestomach tumorigenesis in the double mutant mice. Our results point strongly to the crucial relevance of synergy between Smad4 and PTEN to suppress forestomach tumorigenesis through the cooperative induction of cell cycle inhibitors.

Carbon (C) plays an important role in the interaction between plant and rhizosphere microbial communities, but there is still limited information about how C source utilization soil microbial structure responds to soil fertility changes under the double‐cropping rice (Oryza sativa L.) system in Southern China paddy fields. Therefore, the effects of long‐term (33 years) fertilizer regimes on the characteristics of C utilization in both rhizosphere and nonrhizosphere soils under double‐cropping rice fields in Southern China were investigated by using the metagenome sequencing technology. The experiment began in 1986, and included five fertilizer treatments: without fertilizer input (CK), chemical fertilizer alone (MF), rice straw residue and chemical fertilizer (RF), 30% organic matter, and 70% chemical fertilizer (LOM), and 60% organic matter and 40% chemical fertilizer (HOM). The results showed that the relative abundance of Gemmatimonadetes and Planctomycetia in both the rhizosphere and nonrhizosphere soils was increased by application of rice straw residue and organic manure, whereas the relative abundance of Gammaproteobacteria and Nitrospira was promoted by application of inorganic fertilizers. The largest group of clusters of orthologous groups of proteins categories was “amino acid transport and metabolism” with 16.46% unigenes, followed by “general function prediction only” (12.23%). Regarding the gene ontology categories, biological process were the largest category (174 949, 46.40%), followed by cellular component (126 766, 33.62%), and molecular function (110 353, 29.26%). The principal coordinate analysis indicated that different parts of the root zone were the most important factors affecting the variation of C source utilization bacteria community, and the different fertilizer treatments were the second important factor affecting the variation of C source utilization bacteria community. As a result, the application of fertilization practices had significant effects on the abundance and community composition of C source utilization microbes in paddy soils. The results showed that the combined application of rice straw residue or organic manure with chemical fertilizer practices significantly increases the C source utilization of soil microorganisms in double‐cropping rice fields.