Summary
Rice grain filling rate contributes largely to grain productivity and accumulation of nutrients. MicroRNAs (miRNAs) are key regulators of development and physiology in plants and become a ...novel key target for engineering grain size and crop yield. However, there is little studies, so far, showing the miRNA regulation of grain filling and rice yield, in consequence. Here, we show that suppressed expression of rice miR1432 (STTM1432) significantly improves grain weight by enhancing grain filling rate and leads to an increase in overall grain yield up to 17.14% in a field trial. Molecular analysis identified rice Acyl‐CoA thioesterase (OsACOT), which is conserved with ACOT13 in other species, as a major target of miR1432 by cleavage. Moreover, overexpression of miR1432‐resistant form of OsACOT (OXmACOT) resembled the STTM1432 plants, that is, a large margin of an increase in grain weight up to 46.69% through improving the grain filling rate. Further study indicated that OsACOT was involved in biosynthesis of medium‐chain fatty acids. In addition, RNA‐seq based transcriptomic analyses of transgenic plants with altered expression of miR1432 demonstrated that downstream genes of miR1432‐regulated network are involved in fatty acid metabolism and phytohormones biosynthesis and also overlap with the enrichment analysis of co‐expressed genes of OsACOT, which is consistent with the increased levels of auxin and abscisic acid in STTM1432 and OXmACOT plants. Overall, miR1432‐OsACOT module plays an important role in grain filling in rice, illustrating its capacity for engineering yield improvement in crops.
We carried out a pool culture experiment to determine the optimal water treatment depth in loam and clay soils during the late growth stage of super rice. Three controlled water depth treatments of ...0-5, 0-10 and 0-15 cm below the soil surface were established using alternate wetting and drying irrigation, and the soil water potential （0 to -25 kPa） was measured at 5, 10 and 15 cm. A 2-cm water layer was used as the control. We measured soil enzyme activities, root antioxidant enzyme activities, chlorophyll fluorescence parameters, and rice yield. The results showed that the 0-5-cm water depth treatment significantly increased root antioxidant enzyme activities in loam soil compared with the control, whereas soil enzyme activities, chlorophyll fluorescence parameters and yield did not differ from those of the control. The 0-10- and 0-15-cm water depth treatments also increased root antioxidant enzyme activities, whereas soil enzyme activities, chlorophyll fluorescence parameters and yield decreased. In clay soil, the soil enzyme activities, root antioxidant enzyme activities, chlorophyll fluorescence parameters, and yield did not change with the 0-5-cm water treatment, whereas the 0-10- and 0-15-cm water treatments improved these parameters. Therefore,the appropriate depths for soil water during the late growth period of rice with a 0 to -25 kPa water potential were 5 cm in loam and 15 cm in clay soil.
Superior grains determined by grain weight are not fully correlated with the flowering order in rice PENG Ting, L Qiang, ZHAO Ya-fan, SUN Hong-zheng, HAN Ying-chun, DU Yan-xiu, ZHANG Jing, LI Jun-zhou, WANG Lin-lin, ZHAO Quan-zhi (State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou 310006, P.R.China)
Journal of Integrative Agriculture,
05/2015, Letnik:
14, Številka:
5
Journal Article
Recenzirano
Odprti dostop
Rice panicles are composed of many branches with two types of extreme grains,the superior and the inferior.Traditionally,it has been well accepted that earlier flowers result in superior grains and ...late flowers generate inferior grains.However,these correlations have never been strictly examined in practice.In order to determine the accurate relationship between superior and inferior grains and the flowering order,we localized all the seeds in a panicle in four distinct rice species and systematically documented the rice flowering order,flower locations and the final grain weight for their relationships.Our results demonstrated that the grain weight is more heavily determined by the position of the seeds than by the flowering order.Despite earlier flowering has a positive correlation with the grain weight in general,grains from flowers blooming on the second day after anthesis generally gained the highest weight.This suggests earlier flowers may not result in superior grains.Therefore,we concluded that superior and inferior grains,commonly determined by grain weight,are not fully correlated with the flowering order in rice.Following the order of the grain weight,the superior grains are generally localized at the middle parts of the primary branches,whereas inferior grains were mainly on the last two secondary branches of the lower half part of the panicle.In addition,the weight of inferior grains were affected by spikelet thinning and spraying with exogenous plant growth regulators,indicating that physiological incompetence might be the major reason for the occurrence of the inferior grains.
Test of Small RNA Sequencing Repeatability in Rice SUN Hong-zheng PENG Ting ZHANG Jing LI Jun-zhou DU Yan-xiu ZHAO Quan-zhi
Rice science,
2017, January 2017, 2017-01-00, 2017-01-01, Letnik:
24, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Deep sequencing of small RNAs（sR NA） is widely used in sR NAs studies in plants. In order to investigate the sequencing frequency variation of sR NAs, the same sR NA samples from rice grains were ...sequenced twice using deep sequencing technique. The sR NAs were classified into three categories, high abundance（〉 100 RPM）, medium abundance（10–100 RPM） and low abundance（1–10 RPM）. According to the repeat sequencing data of the same sample, highly expressed sR NAs（〉 100 RPM） were less subject to random drift, and 95% of the sR NAs Log2 ratio between two samples fell between-0.649 and 0.558. The same trend was observed in mediumly expressed sR NAs（10–100 RPM）, and 95% of the Log2 ratio fell between-0.535 and 0.759. As to lowly expressed sR NAs（1–10 RPM）, 95% of the Log2 ratio varied between-1.009 and 1.011. These results can be used as a theoretical guide to find differentially expressed s RNAs in sR NA studies in plants.
Sugarcane mosaic virus (SCMV) is one of the devastating virus diseases of maize in the world. Understanding the genetic of resistance gene(s) is the basis for effective selection in resistance ...breeding program. In this study, analyses were conducted to determine the genetic basis in line Siyi with tropic germplasm conferring complete resistance to SCMV. Based on the responses of parents and F₁, F₂ and backcross populations in three successive years' field trails, two dominant complementary genes, were found to condition the resistance by Mendelian genetic analysis. The two genes were mapped on chromosome 3 and chromosome 6, respectively using microsatellite markers. The resistance gene on chromosome 3 (bin 3.04/05) was flanked by simple sequence repeat markers umc1527 and phi053 with the genetic distances of 1.8 and 2.1 cM, respectively; whereas the genetic distances between the two flanking markers umc2311 and bnlg1371 and resistance gene on chromosome 6 (bin 6.00/01) was 2.1 and 1.5 cM, respectively. Genotypic analysis of the plants from backcross and F₃ populations also validated the two genes with the unique genetic model. For further confirming the interaction between the two genes, a set of near isogenic lines (NILs) carrying different number of the resistance genes were developed, genotypic analysis of NILs clearly show that two dominant complementary genes cooperatively control the resistance to SCMV in maize.
The effect of sulphate nutrition on arsenic (As) concentration, photosynthetic and chlorophyll fluorescence parameters of rice was investigated in hydroponically grown rice seedlings (Oryza sativa ...L.), using three sulphate levels (1.8 μM, 0.7 mM, or 1.5 mM). The results showed that sulphate deficiency decreased As accumulation in root, but increased the translocation of As from root to shoot. Sulphate deficiency reduced maximum quantum yield (Fv/Fm), minimum fluorescence and electron transport rate (ETR) of a dark-adapted leaf. Compared with low sulphate treatments (1.8 μM), significant increases were observed in the parameters of rapid light curves, rETRₘₐₓ and I ₖ of photosystem I (PSI) and photosystem II (PSII) of rice grown in the high sulphate treatments (1.5 mM) regardless of As additions. Therefore, an adequately high sulphate supply may result in less As translocation from root to shoot, and protecting the reaction pathways of PSI and PSII of rice seedlings grown in higher As-contaminated medium.
To understand the effects of silicon on the growth and development of rice roots, a hydroponic experiment with 3 levels of silicon, i.e., no silicon (T1), 1.25 mmol silicon x L(-1) (T2), and 2 mmol ...silicon x L(-1) (T3), was conducted, using rice cultivars TN1 and Baixiangjing with high silicon uptake efficiency and Juanyejing and Hitomebore with low silicon uptake efficiency as test materials. The results showed that with the increase of silicon supply, the root dry mass, root-shoot ratio, lateral root number, and total root length of all test rice cultivars decreased, while the dry mass of above-ground parts, root number, and root diameter increased. Relatively higher silicon supply was beneficial to the differentiation and development of indefinite roots, but not favorable to the lateral roots. Under lower silicon supply, the root dry mass and root-shoot ratio of TN1 and Baixiangjing were significantly higher than those of Juanyejing and Hitomebore. Furthermore, the number of lateral roots and the total roo
Summary
Rice grain filling rate contributes largely to grain productivity and accumulation of nutrients. Micro
RNA
s (mi
RNA
s) are key regulators of development and physiology in plants and become a ...novel key target for engineering grain size and crop yield. However, there is little studies, so far, showing the mi
RNA
regulation of grain filling and rice yield, in consequence. Here, we show that suppressed expression of rice miR1432 (
STTM
1432) significantly improves grain weight by enhancing grain filling rate and leads to an increase in overall grain yield up to 17.14% in a field trial. Molecular analysis identified rice Acyl‐CoA thioesterase (
Os
ACOT
), which is conserved with
ACOT
13 in other species, as a major target of miR1432 by cleavage. Moreover, overexpression of miR1432‐resistant form of
Os
ACOT
(
OX
m
ACOT
) resembled the
STTM
1432 plants, that is, a large margin of an increase in grain weight up to 46.69% through improving the grain filling rate. Further study indicated that
Os
ACOT
was involved in biosynthesis of medium‐chain fatty acids. In addition,
RNA
‐seq based transcriptomic analyses of transgenic plants with altered expression of miR1432 demonstrated that downstream genes of miR1432‐regulated network are involved in fatty acid metabolism and phytohormones biosynthesis and also overlap with the enrichment analysis of co‐expressed genes of
Os
ACOT
, which is consistent with the increased levels of auxin and abscisic acid in
STTM
1432 and
OX
m
ACOT
plants. Overall, miR1432‐
Os
ACOT
module plays an important role in grain filling in rice, illustrating its capacity for engineering yield improvement in crops.
The analysis of virus genome is based on nucleic acid isolation. The aims of this study were to develop a method for isolation and identification of virus double-stranded ribonucleic acid （dsRNA） and ...to elucidate the nucleotide sequences of strawberry virus. Using the modified method, virus dsRNA was extracted from strawberry virus indicator plants and cultivated strawberry plants and detected using agarose gel electrophoresis with ethidium bromide staining and reverse transcription-polymerase chain reaction （RT-PCR）. The quantity of virus dsRNA varied among strawberry cultivars. The quantity of dsRNA from in vitro plantlets was higher than that from the young leaves of field plants. For the field-grown plants, there was more dsRNA in the young leaves. Virus dsRNA extracted from strawberry plants was resistant to deoxyribonuclease Ⅰ （DNase Ⅰ）, but evidently, it became resistant to ribonuclease A （RNase A） only in the presence of 0.5 M NaCl. Its bands in agarose gel could be readily recycled using an agarose gel DNA purification kit. With RT-PCR, the segments of both strawberry mottle virus and Strawberry mild yellow edge virus genomes were amplified by using the virus dsRNA recycled from gel or treated with DNase Ⅰ /RNase A as templates. The system developed for dsRNA isolation and identification in strawberry plants laid a sound foundation for the work on genome analysis of strawberry virus isolates in China.
Rice panicles are composed of many branches with two types of extreme grains, the superior and the inferior. Traditional y, it has been wel accepted that earlier lfowers result in superior grains and ...late lfowers generate inferior grains. However, these correlations have never been strictly examined in practice. In order to determine the accurate relationship between superior and inferior grains and the lfowering order, we localized al the seeds in a panicle in four distinct rice species and systematical y documented the rice lfowering order, lfower locations and the ifnal grain weight for their relationships. Our results demonstrated that the grain weight is more heavily determined by the position of the seeds than by the lfowering order. Despite earlier lfowering has a positive correlation with the grain weight in general, grains from lfowers blooming on the second day after anthesis general y gained the highest weight. This suggests earlier lfowers may not result in superior grains. Therefore, we concluded that superior and inferior grains, commonly determined by grain weight, are not ful y cor-related with the lfowering order in rice. Fol owing the order of the grain weight, the superior grains are general y localized at the middle parts of the primary branches, whereas inferior grains were mainly on the last two secondary branches of the lower half part of the panicle. In addition, the weight of inferior grains were affected by spikelet thinning and spraying with exogenous plant growth regulators, indicating that physiological incompetence might be the major reason for the occurrence of the inferior grains.
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