叶片的光合作用主要发生在叶绿体中，叶绿体的发育受核基因编码蛋白调控。其中，PPR蛋白参与细胞器RNA编辑。在水稻中虽然鉴定出了约450个PPR蛋白家族成员，但只有少数被证明影响水稻叶绿体RNA编辑。利用基因编辑技术创造了新的水稻种质资源和突变体，能够用于水稻育种和基因功能研究。本研究鉴定了一个DYW类型PPR蛋白OsPPR9在水稻叶绿体RNA编辑中的功能。通过CRISPR/Cas9基因编辑技术获得了Osppr9突变体，该突变体叶片黄化和致死表型；在突变体中，叶绿体发育相关基因表达量降低，光合作用相关蛋白的积累减少。此外，OsPPR9蛋白功能的缺失降低了叶绿体中rps8-C182, rpoC2-C4106, rps14-C80和ndhB-C611 RNA编辑位点的编辑效率，影响水稻叶绿体的生长发育。OsPPR9在水稻叶片中表达量最高和编码一个定位于叶绿体的PPR蛋白。此外，通过酵母双杂验证OsPPR9与OsMORF2和OsMORF9相互作用。总之，我们的研究为探明PPR蛋白在水稻叶绿体发育中的作用提供了线索。 

小麦-玉米轮作体系减磷措施调控土壤磷素有效性与微生物间的耦合机制研究鲜有报道。本研究基于初始高磷（30.36 mg kg^-1）和低磷水平（9.78 mg kg^-1）石灰性土壤，通过连续四季的盆栽试验（2016-2018），探究小麦-玉米轮作体系仅麦季施磷（Pw）较常规麦-玉两季均施磷肥（Pwm）措施对作物产量、土壤有效磷和微生物群落结构的影响。结果表明，高磷水平Pw处理较Pwm处理每年减少33.3%的磷肥投入情况下，作物总产量能够连续两年稳产。玉米大喇叭口期，Pw处理土壤水溶性磷浓度与Pwm处理含量无显著差异。土壤磷含量显着影响土壤微生物群落，尤其是真菌群落。Pw处理变形菌门的相对丰度和碱性磷酸酶（ALP）活性显著高于Pwm处理（分别为11.4和13.3％）。高磷水平下，土壤微生物对产量的贡献大于土壤有效磷的影响。Pw处理芽孢杆菌和根瘤菌相对丰度显著高于Pwm处理。芽孢杆菌与酸性磷酸酶（ACP）活性呈显着正相关，根瘤菌与ACP和ALP活性均呈显着正相关，可能利于土壤磷素活化。本研究说明高磷土壤条件下，小麦-玉米轮作体系仅麦季施磷可通过土壤磷有效性与微生物间的耦合实现全年作物稳产。

本研究为了量化不同“C饥饿”水平下玉米叶片C固定及其分配，并分析其与植株适应性生长之间的关系，利用室内液体培养玉米植株，在6叶展期进行连续三天的延长黑暗（ED）处理。结果表明，ED处理显著降低了植株生长和叶片叶绿素水平，但单位叶片CO₂气体交换速率没有明显变化。由于延长黑暗缩短了光合时长，降低了日光合同化产物积累，成熟叶片中的淀粉和可溶性碳水化合物（TSC）日累积量也呈下降趋势。然而，ED处理下叶片淀粉和TSC积累量占日同化C总量的比例却有所增加。这些“暂储性”C大部分以TSC形式存在，并且主要为增加的夜间呼吸消耗所用而非转运至库器官。另一方面，随着时间的推移，不同处理叶片中的“暂储性”C累积量及其占日同化C总量的比例均呈下降趋势，这主要是由于叶片淀粉合成下降所致。叶片中的腺苷二磷酸葡萄糖焦磷酸化酶和可溶性淀粉合酶活性随时间推移显著下降。因此，我们认为淀粉和TSC都参与了C突然短缺时植株生长和C供应之间的协调，但可能存在不同的作用方式。在突然的“C饥饿”情况下，植株将更高比例的同化产物留存在叶片中，以维持叶片功能。同时，成熟叶片中的“暂储性”C量及其占日同化C总量的比例随时间推移不断下降，以满足库器官的持续性生长需求。

Received  2 August, 2017    Accepted  31 October, 2017
 © 2018, CAAS. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)
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    Alcohol dehydrogenase (ADH) catalyzes the interconversion of aldehydes and their corresponding alcohols, and is a key enzyme in volatile ester biosynthesis. However, little is known regarding ADH and ADH encoding genes (ADHs) in pear. We identified 8 ADHs in the pear’s genome (PbrADHs) by multiple sequences alignment. The PbrADHs were highly homologous in their coding regions, while were diversiform in structure. 9 introns were predicted in PbrADH₃–PbrADH₈, while 8 introns, generated through exon fusion and intron loss, were predicted in PbrADH₁ and PbrADH₂. To study the genetic regulation underlying aroma biogenesis in pear fruit, we determined the PbrADH transcripts, ADH activities and volatile contents of fruits during ripening stage for Nanguoli and Dangshansuli, two cultivars having different aroma characteristics. ADH activity was strongly associated with the transcription of ADH6 in the two cultivars during fruit ripening stage. The higher ester content paralleling to a higher ADH activity was detected in Nanguoli than in Dangshansuli, so it is induced that the lower ester content in Dangshansuli fruit may be the result of weak ADH activity. The present study revealed that total ADH activity and volatile ester production correlated with increased PbrADH₆ transcript levels. PbrADH6 may contribute to ADH activity catalyzing aldehyde reduction and ester formation in pear fruit.

The genus Adelphocoris (Hemiptera: Miridae) is a group of key insect pests in cotton fields in China that includes three dominant species: A. suturalis (Jakovlev), A. lineolatus (Goeze) and A. fasciaticollis (Reuter). Previous field surveys have found that adults of these Adelphocoris species usually move onto specific host plants when the plants enter the flowering stage. To determine the potential trade-offs for this host-plant preference behavior, the performance of these three Adelphocoris spp. on flowering and non-flowering cotton and alfalfa were compared in the laboratory. The results showed that Adelphocoris spp. had significantly higher nymphal developmental and survival rates, along with increased adult longevity and fecundity on flowering cotton and alfalfa than on non-flowering plants of either species. In addition, compared with cotton plants, alfalfa generally promoted better performance of these three Adelphocoris species, especially for A. lineolatus. Simple correlation analysis indicated that female adult longevity was positively correlated to male adult longevity and female fecundity, and female fecundity was positively correlated to nymphal development and survival rates. This study demonstrated a positive correlation between adult preference and offspring/adult performance for all three Adelphocoris species, with no evidence of any trade-offs for this preference for flowering host plants. These findings support the hypothesis that hemimetabolous insects such as mirid bugs have positive adult preference-adult/nymphal performance relationships, which is likely due to the similar feeding habits and nutritional requirements of adults and nymphs.

Complete genome sequence of Potato virus Y Liaoning isolate (PVY-LN) causing tobacco vein necrosis symptoms were isolated from Liaoning Province in China. Genome sequences of PVY-LN was 9 714 nucleotides in length, excluding the 3´- terminal poly (A) tail. PVY-LN encodes a single long open reading frame (ORF) of polyprotein that is predicted to be cleaved into ten mature proteins by three viral proteases. No recombination can be predicted in PVY-LN sequences compared with that of the other PVY strains using Recombination Detection Programe v. 4.16 (RDP4). Complete genome sequence comparison and phylogenetic analysis indicated that PVY-LN is closely related to PVY necrosis strain (PVYN).