Detection of QTLs controlling fast kernel dehydration in maize (Zea mays L.).

In order to understand the effect of grain moisture of inbred lines at the silking and physiological maturity stages on kernel dehydration rate, 59 maize inbred lines from six subgroups were selected. Grain moisture was measured and QTLs associated with kernel dehydration were mapped. A rapid dehydration evaluation and association analysis revealed eight inbred lines with faster dehydration rate, including Yuanwu 02, K36, Zhonger/O2, Lo1125, Han 49, Qi 319, Hua 160, and PH4CV. A single sequence repeat analysis using 85 pairs detected five QTLs with phenotypic variation contribution ≥10% in the permanent F2 generation populations Zheng 58 x S1776 and Chang 7-2 x K1131, which had LOD threshold values ≥ 3 in both 2013 and 2014. The chromosome region of qFkdr7b had not previously been reported and is preliminarily identified as a new major QTL. A false positive field verification of grain dehydration rate of 53 inbred lines indicated that the screening result of the rapid dehydration inbred lines by specific amplification with marker Phi114 was most similar to the field assessment result, followed by markers Phi127 and Phi029. The rapid dehydration lines selected based on primer Phi114 amplification were also similar to the field dehydration rate and can thus be used for molecular marker-assisted selection. A significant effort is needed to improve stress resistance and shorten the growth period via fast kernel dehydration in intermediate materials of the inbred lines K36, Zhonger/ O2, Lo1125, Han 49, Hua 160, and PH4CV, and further using the selected lines for new combinations.

[The effect of nerve growth factor on the expression of BMP-2 in the healing of rabbits' mandibular fracture with partial nerve injury].

Objective:To observe the effect of NGF on the expression of BMP-2 in rabbit model and explore the molecular mechanism of NGF which might promote the healing of mandibular fracture with nerve injury. Method:The 48 New-Zealand white rabbits were randomly divided into the experimental group (mandibular fracture+to cut off the nerve bundle+NGF by GS), the control group (mandibular fracture+to cut off the nerve bundle+NS by GS), the blank group (mandibular fracture+to cut off the nerve bundle) and the full-set group (mandibular fracture+retains the nerve bundle). After 2 weeks, 4 weeks, 6 weeks and 8 weeks, 3 rabbits were sacrificed in each group for HE staining and RT-PCR, respectively. Result:HE staining showed the osteogenesis phenomenon: the experimental group was clearer than control group, the full-set group was clearer than the blank group and the control group is similarly to the blank group. RT-PCR results revealed that there was a statistically significance in the early stage. The expression of BMP-2 peaked in 2 weeks and decreased later with time. Conclusion:The local application of NGF can prompt BMP-2 expression in the early stages of the mandibular fracture with partial nerve injury healing and this may be one of the molecular mechanisms.