Wx^lv、the Ancestral Allele of Rice Waxy Gene

In rice grains,the Waxy (Wx) gene is responsible for the synthesis of amylose,the most important determinant for eating and cooking quality.The effects of several Wx alleles on amylose content and the taste of cooked rice have been elucidated.However,the relationship between artificial selection and the evolution of various Wx alleles as well as their distribution remain unclear.Here we report the identification of an ancestral allele,Wx^lv,which dramatically affects the mouthfeel of rice grains by modulating the size of amylose molecules.We demonstrated that WF originated directly from wild rice,and the three major Wx alleles in cultivated rice (Wx^b,Wx^a,and Wx^in) differentiated after the substitution of one base pair at the functional sites.These data indicate that the Wx^lv allele played an important role in artificial selection and domestication.The findings also shed light on the evolution of various Wx alleles,which have greatly contributed to improving the eating and cooking quality of rice.

A rare Waxy allele coordinately improves rice eating and cooking quality and grain transparency

In rice(Oryza sativa), amylose content(AC) is the major factor that determines eating and cooking quality(ECQ). The diversity in AC is largely attributed to natural allelic variation at the Waxy(Wx)locus. Here we identified a rare Wx allele, Wx^(mw) ,which combines a favorable AC, improved ECQ and grain transparency. Based on a phylogenetic analysis of Wx genomic sequences from 370 rice accessions, we speculated that Wx^(mw) may have derived from recombination between two important natural Wx alleles, Wx^(in) and Wx^(b). We validated the effects of Wx^(mw) on rice grain quality using both transgenic lines and near-isogenic lines(NILs). When introgressed into the japonica Nipponbare(NIP) background, Wx^(mw) resulted in a moderate AC that was intermediate between that of NILs carrying the Wx^(b)allele and NILs with the Wx^(mp) allele. Notably, mature grains of NILs fixed for Wx^(mw) had an improved transparent endosperm relative to soft rice. Further, we introduced Wx^(mw) into a high-yielding japonica cultivar via molecular marker-assisted selection: the introgressed lines exhibited clear improvements in ECQ and endosperm transparency. Our results suggest that Wx^(mw) is a promising allele to improve grain quality, especially ECQ and grain transparency of high-yielding japonica cultivars, in rice breeding programs.

Prognostic significance of combining high mobility group Box-1 and OV-6 expression in hepatocellular carcinoma

The inflammatory environment and existence of cancer stem cells are critical for progression and intrahepatic recurrence of hepatocellular carcinoma(HCC) after curative resections. Here, we investigated the prognostic significance of combining high mobility group box 1(HMGB1) expression and hepatic progenitor marker OV6 in hepatocellular carcinoma. Expression of HMGB1 and OV6 was evaluated using immunohistochemistry profiling in tissue microarrays containing samples from 208 HCC patients. Invasive clinical or pathological factors were found in patients with high expression of HMGB1 or OV6. Higher HMGB1 was associated with poorer clinical outcomes, and independently related to elevated 5-year recurrence incidence(85.5% vs. 62.4%, P<0.001). We also found that more OV6 positive staining was correlated with poor prognosis of HCC patients(P<0.001). Notably, expression of HMGB1 was positively correlated with OV6 in density(R2=0.032, P<0.001) and reversely related to HCC outcomes. Abnormal expression of HMGB1 in combination with positive staining of OV6 displayed poorer prognostic performance than single biomarker alone(area under curve(AUC) survival=0.696). Therefore, HMGB1 and OV6 positive staining are promising prognostic parameters for HCC, and we propose that HMGB1 and OV6 may cooperate with each other and predict poor prognosis of HCC.