Genome-wide identification and expression analysis of the KNOX family and its diverse roles in response to growth and abiotic tolerance in sweet potato and its two diploid relatives.

KNOXs, a type of homeobox genes that encode atypical homeobox proteins, play an essential role in the regulation of growth and development, hormonal response, and abiotic stress in plants. However, the KNOX gene family has not been explored in sweet potato. In this study, through sequence alignment, genomic structure analysis, and phylogenetic characterization, 17, 12 and 11 KNOXs in sweet potato (I. batatas, 2n = 6x = 90) and its two diploid relatives I. trifida (2n = 2x = 30) and I. triloba (2n = 2x = 30) were identified. The protein physicochemical properties, chromosome localization, phylogenetic relationships, gene structure, protein interaction network, cis-elements of promoters, tissue-specific expression and expression patterns under hormone treatment and abiotic stresses of these 40 KNOX genes were systematically studied. IbKNOX4, -5, and - 6 were highly expressed in the leaves of the high-yield varieties Longshu9 and Xushu18. IbKNOX3 and IbKNOX8 in Class I were upregulated in initial storage roots compared to fibrous roots. IbKNOXs in Class M were specifically expressed in the stem tip and hardly expressed in other tissues. Moreover, IbKNOX2 and - 6, and their homologous genes were induced by PEG/mannitol and NaCl treatments. The results showed that KNOXs were involved in regulating growth and development, hormone crosstalk and abiotic stress responses between sweet potato and its two diploid relatives. This study provides a comparison of these KNOX genes in sweet potato and its two diploid relatives and a theoretical basis for functional studies.

[Determination of microelements from different types of grass in the habitat of Przewalski's gazelle by sealed microwave digestion ICP-AES].

For the mixture forge from different types of grassland, trace elements including copper, manganese, iron, zinc and molybdenum were separately determined by ICP-AES using high pressure system-sealed microwave digestion in the habitat of the Przewalski's gazelle in Qinghai Hudong in summer (mid-June), autumn (mid-September) and winter (mid-December). The samples of mixture forage were digested with HNO3-H2O2 acids system. The detection limits of the method for the elements varied from 0.002 to 0.008 microg x g(-1), with relative standard deviations between 0.13% and 4.29%, and the spike recovery ratios for them were in the range from 94.0% to 101.30%. This method was simple, sensitive and precise compared with conventional method, which will provide scientific basis for the research on gazelles habitat condition.

[Determination of inorganic elements in chicken muscle by sealed microwave digestion ICP-AES].

The contents of inorganic elements including K, Ca, Na, Mg, P, S, Fe, Cu, Mn, Zn, Mo, and Co from the chicken muscle were determined by ICP-AES using sealed microwave digestion. The sample of the chicken muscle was digested with HNO3-H2O2 system. The relative standard deviation was less than 5% for all the elements, and the recovery was 92.5%-110% by adding standard recovery experiment. This method was simple, sensitive and precise and can perform simultaneous multi-elements determination compared with conventional method of the chicken muscle determination, which could satisfy the sample examination request and provide scientific rationale for determining inorganic elements of chicken meat.

[Determination of inorganic elements in the soil-grass-animal system by sealed microwave digestion ICP-AES].

The contents of inorganic elements including K, Ca, Na, Mg, P, S, Fe, Cu, Mn, Zn, Mo, and Co in the soil-grass-animal mineral system from Qinghai Tibetan Plateau were determined by ICP-AES using high pressure system-sealed microwave digestion. The sample of soil was digested with HNO3-HF-H2O2 acids system, but others including pasture, animal fur, liver, and serum were digested with HNO3-H2O2 acids system. The operation would be simplified and the blank value would be decreased with the above acids systems. The results were proved to be reliable with the relative standard deviation being 0.271%-2.633% for Ca, 2.971%-4.854% for Co, 0.372%-2.874% for Cu, 0.600%-3.683% for Fe, 0.347%-2.829% for K, 0.626%-2.593% for Mg, 0.705%-4.828% for Mn, 2.946%-4.622% for Mo, 0.689%-3.621% for Na, 0.422%-3.890% for P, and 0.143%-4.622% for S, 0.166%-2.399% for Zn, and all of them were less than 5% for all the elements, and the recovery being 97.1%-101.4% for Ca, 93.5%-112.5% for Co, 95.2%-104.0% for Cu, 96.9%-104.2% for Fe, 96.1%-105.6% for K, 96.2%-102.8% for Mg, 91.5%-108.9% for Mn, 95.0%-113.5% for Mo, 95.2%-101.8% for Na, 94.7%-100.7% for P, 98.3%-108.4% for S, and 97.5%-102.0% for Zn by adding standard recovery experiment. The results of determination were proved that the method of sealed microwave digestion ICP-AES was sensitive, precise, easy to operate and rapid for the determination of inorganic elements in the soil-grass-animal mineral system, and could satisfy the sample examination request. The methods and results were meaningful to research on the soil-pasture-animal mineral system including the contents of mineral elements, the circulation of mineral elements, the interaction, and the application of mineral additive.