Yield loss due to low precipitation use efficiency (PUE) occurs frequently in dryland crop production.  PUE is determined by a complicated process of precipitation use in farmland, which includes several sequential steps: precipitation infiltrates into the soil, the infiltrated precipitation is stored in soil, the soil-stored precipitation is consumed through transpiration or evaporation, transpired precipitation is used to produce dry-matter, and finally dry-matter is re-allocated to grains.  These steps can be quantified by six ratios: precipitation infiltration ratio (SW/SWe; SW, total available water; SWe, available soil water storage at the end of a specific period), precipitation storage ratio (SWe/P; P, effective precipitation), precipitation consumption ratio (ET/SW; ET, evapotranspiration), ratio of crop transpiration to evapotranspiration (T/ET; T, crop transpiration), transpiration efficiency (B/T; B, the increment of shoot biomass) and harvest index (Y/B; Y, grain yield).  The final efficiency is then calculated as: PUE=SWe/P×SW/SWe×ET/SW×T/ET×B/T×Y/B.  Quantifying each of those ratios is crucial for the planning and execution of PUE improvements and for optimizing the corresponding agronomic practices in a specific agricultural system.  In this study, those ratios were quantified and evaluated under four integrated agronomic management systems.  Our study revealed that PUE and wheat yield were significantly increased by 8–31% under manure (MIS) or biochar (BIS) integrated systems compared to either conventional farmers’ (CF) or high N (HN) integrated systems.  In the infiltration and storage steps, MIS and BIS resulted in lower SWe/P but higher SW/SWe compared with CF and HN.  Regarding the consumption step, the annual ET/SW under MIS and BIS did not increase due to the higher ET after regreening and the lower ET before regreening compared with CF or HN.  The T/ET was significantly higher under MIS and BIS than under CF or HN.  In the last two steps, transpiration efficiency and harvest index were less strongly affected by the agronomic management system, although both values varied considerably across the different experimental years.  Therefore, attempts to achieve higher PUE and yields in rainfed wheat through agronomic management should focus on increasing the T/ET and SW/SWe, while maintaining ET/SW throughout the year and keeping SWe/P relatively low at harvest time.

In this study, the characteristic of three transformants named as B1C106-1, B1C106-2, and B1C106-3 were studied that carried three innate resistant genes Bph14, Bph15, and Xa23, and two enthetic resistant genes Cry1Ca^# and Bar.  The five resistant genes were all verified by PCR and the two enthetic genes were identified in single copy insertion by Southern blot.  At tillering stage, the Cry1C and PAT (phosphinothricin acetyl transferase) protein contents in leaf, sheath, and stem of T₂ generation were in the similar pattern: leaf>stem>sheath, and showed significant difference (P<0.01) among three organs. The average contents of Cry1C protein in plant of B1C106-1, B1C106-2, and B1C106-3 were 12.95, 6.57, and 11.30 μg g^–1, respectively, and showed significant difference (P<0.01) among them.  However, the average contents of PAT in plant of B1C106-1, B1C106-2, and B1C106-3 were 28.54, 27.66, and 28.02 μg g^–1, respectively, and there were no significant difference among three transformants.  The glufosinate tolerable concentration of three transformants of T₃ generation reached at least 6 g L^–1, and the mortality of rice leaf rollers were above 97.4% in 5 days after being fed with fresh transformants’ leaves.  The Cry1C protein toxicity was also assessed by silkworms, and the mortality of silkworms feeding mulberry leaves smeared with Cry1C protein extracts of leaves of B1C106-1, B1C106-2, and B1C106-3 were 90, 67.8, and 87.8%, respectively, that were positive correlation (r=0.993) with Cry1C protein contents in plant of three transformants.  The three transformants also maintained high resistance to brown planthopper and bacterial blight as the original version.  The above results indicate the tetra-resistant rice germplasm was well-developed by pyramiding innate and enthetic resistant genes in an elite line to provide with resistances of glufosinate, rice leaf roller, brown planthopper, and bacterial blight.  

The developing trends of livestock production are efficiency, safety and sustainability, which face two major challenges: low availability of phytate phosphorus and abuse of antibiotics.  As a solution phytases and antimicrobial peptides are applied as feed additives.  However, phytases and antimicrobial peptides are susceptible to proteases, costly by fermentation and potential toxic to production hosts.  We transformed an optimized phytase-lactoferricin fusion gene PhyLf driven by an endosperm-specific promoter Gt13aP and Bar (bialaphos resistance) gene as a selection maker into rice.  The Bar and PhyLf genes were integrated into the rice genome, stably inherited and expressed.  Their phosphinothricin acetyl transferase (PAT) protein content of transgenic plants with glufosinate resistance varied between 50.45–93.39 μg g^–1.  Fusion protein expressed especially in the seeds of transgenic rice had a summit phytase activity at 32.30 U g^–1, which increased by 61.71-fold compared to the control/check group (CK) and 7.54-fold compared to un-optimized transgenic plant.  The highest inorganic phosphorus (Pi) content of the transgenic seeds reached 13.15 mg g^–1, increased by 12.77-fold compared to that of CK.  Preliminary antibacterial experiments showed that the enterokinase hydrolysate product of fusion protein could inhibit the growth of Escherichia coli DH5α.  These results indicated that the protein PhyLf has the potential to increase availability of feed phytate phosphorus, improve consumer’s immunity and reduce the use of antibiotics.

Contamination of deoxynivalenol (DON) in grains is common worldwide and pigs are particularly susceptible to this mycotoxin. The distribution of DON in porcine tissues following intravenous administration was investigated in this study. Fifteen pigs were randomly divided into three groups. Animals in groups A and B were administrated with DON at the dose of 250 and 750 μg kg–1 body weight, respectively, while group C served as blank control. Plasma, bile and 27 tissues were collected at 30 min post-administration. DON concentrations in all samples were tested using high-performance liquid chromatography- tandem mass spectrometry (HPLC-MS/MS). To observe the distribution of DON in tissues, these samples were further subjected to the immunohistochemical analyses. Totally, the bile and 13 tissues were sampled for DON-based detection, including kidney, mesenteric lymph nodes, muscle, stomach, jejunum, colon, plasma, spleen, rectum, cecum, liver, ileum, and duodenum. No significant difference was observed for the concentrations of DON in duodenum, ileum and liver samples between groups A and B; while the DON concentrations in cecum and rectum of group B were significantly higher (P-value <0.05) than those in group A. In addition, the DON concentrations in stomach, jejunum, colon, mesenteric lymph nodes, muscle, kidney, spleen, bile, and plasma of group B were remarkably higher than those of group A (P-value<0.01). Levels of DON in other 14 tissues including medulla oblongata, midbrain, diencephalon, pons, tip and tongue body, tongue, soft palate, tonsils, pharyngeal mucosa, oral buccal mucosa, thymus, thyroid, esophagus and adrenal gland were all below the limit of detection. The results of immunohistochemistry showed that 11 tissue samples (medullaoblongata, tonsil, adrenal medulla, thyroid gland, thyroid, stomach, duodenum, jejunum, kidney, spleen, and mesenteric lymph nodes) were positive and DON was mainly distributed around blood vessels in these tissues. Therefore, we believed that concentrations of DON in tissues differ when pigs are in exposure to various dosages and DON causes lesions in many pig tissues.

Two miniature inverted-repeat transposable elements (MITEs), MCLas-A and MCLas-B, were recently identified from ‘Candidatus Liberibacter asiaticus’ known to be associated with citrus Huanglongbing (HLB, yellow shoot disease). MCLas-A was suggested as an active MITE because of its mobility. The immediate upstream gene of the two MITEs was predicted to be a putative transposase. The goal of this study is to analyze the sequence variation in the upstream putative transposase of MITEs and explore the possible correlation between sequence variation of transposase gene and MITE activity. PCR and sequence analysis showed that 12 sequence types were found in six major amplicon types from 43 representative ‘Ca. L. asiaticus’ isolates from China, the United States and Brazil. Out of the 12 sequence types, three (T4, T5-2, T6) were reported for the first time. Recombination events were found in the two unique sequence types (T5-2 and T6) which were detected in all Brazilian isolates. Notably, no sequence variation or recombination events were detected in the upstream putative transposase gene of MCLas-A, suggesting the conservation of the transposase gene might be closely related with the MITE activity. Phylogenetic analysis demonstrated two well supported clades including five subclades were identified, clearly reflecting the geographical origins of isolates, especially that of Ruili isolates, São Paulo isolates and a few Florida isolates.

Citrus fruits are rich in carotenoids. In the carotenoid biosynthetic pathway, lycopene β-cyclase (LCYb, EC:1.14.-.-) is a key regulatory enzyme in the catalysis of lycopene to β-carotene, an important dietary precursor of vitamin A for human nutrition. Two closely related lycopene β-cyclase cDNAs, designated CsLCYb1 and CsLCYb2, were isolated from the pulp of orange fruits (Citrus sinensis). The expression level of CsLCYb genes is lower in the flavedo and juice sacs of a lycopeneaccumulating genotype Cara Cara than that in common genotype Washington, and this might be correlated with lycopene accumulation in Cara Cara fruit. The CsLCYb1 efficiently converted lycopene into the bicyclic β-carotene in an Escherichia coli expression system, but the CsLCYb2 exhibited a lower enzyme activity and converted lycopene into the β-carotene and the monocyclic γ-carotene. In tomato transformation studies, expression of CsLCYb1 under the control of the cauliflower mosaic virus (CaMV) 35S constitutive promoter resulted in a virtually complete conversion of lycopene into β-carotene, and the ripe fruits displayed a bright orange colour. However, the CsLCYb2 transgenic tomato plants did not show an altered fruit colour during development and maturation. In fruits of the CsLCYb1 transgenic plants, most of the lycopene was converted into β-carotene with provitamin A levels reaching about 700 μg g-1 DW. Unexpectedly, most transgenic tomatoes showed a reduction in total carotenoid accumulation, and this is consistent with the decrease in expression of endogenous carotenogenic genes in transgenic fruits. Collectively, these results suggested that the cloned CsLCYb1 and CsLCYb2 genes encoded two functional lycopene β-cyclases with different catalytic efficiency, and they may have potential for metabolite engineering toward altering pigmentation and enhancing nutritional value of food crops.

1 Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, P.R.China 2 Graduate University of Chinese Academy of Sciences, Beijing 100049, P.R.China 3 Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, P.R.China Carotenoid biosynthetic pathway produces not only pigments that protect photosynthetic system against photo-oxidative damage, but also precursors of abscisic acid, the major hormone regulates stress responses. To understand the response of carotenoid biosynthetic pathway to salt stress, the expression of the genes involved in carotenoid and ABA biosynthesis were compared in cultivated tomato Solanum lycopersicon cv. Moneymaker and its relative wild genotype S. pimpinellifolium (PI365967) together with the contents of carotenoids and ABA. The results showed that 11 of the 15 genes investigated were up-regulated and four unaltered in Moneymaker after 5 h of salt stress; whereas only four genes were up-regulated, four unaltered, and seven down-regulated in PI365967 after stress. Further comparison revealed that 11 salinity-induced genes were expressed significantly lower in Moneymaker than in PI365967 under normal condition, and 8 of them were induced to similar levels after salt stress. In consistence, ABA level was doubled in Moneymaker but kept consistent in PI365967 after salt stress, though the contents of neoxanthin, violaxanthin, β-carotene, lutein, and total carotenoids were kept unchanged in both species. Since it is known that PI365967 is more tolerant to salt stress than Moneymaker, we proposed that the constitutive high level of carotenoid and ABA biosynthetic pathway under normal growth condition could be benefit to PI365967 for establishing the early response to salt stress. In addition, CrtR-b1 and CrtR-b2 that encode β-carotenoid hydroxylases were the only genes in carotenoid biosynthetic pathway that were up-regulated by salt stress in both species. The CrtR-b2 gene was cloned from both species and no essential difference was found in the encoded amino acid sequences. Transformation of CrtR-b2 to tobacco improved the seed germination under salt stress condition, indicating that the hydrolysis of β-carotenoid is the target of transcriptional regulation of the carotenoid biosynthesis in both tomato cultivar and wild relative.

The objectives of the present study were to estimate genetic diversity and genetic changes of introgression lines (ILs) which derived from cultivated rice (Oryza sativa L. cv. Xieqingzao B, XB) mating with common wild rice (O. rufipogon Griff., CWR). The genetic data of 239 ILs were based on a total of 131 polymorphic microsatellite (SSR) markers distributed across the 12 chromosomes of rice. On average, these ILs possessed 77.1 and 14.31% homozygous bands from XB and CWR, respectively. Most of the ILs were clustered together with XB individual, which was revealed by principal coordinate analysis (PCA) and the program STRUCTURE analysis. The result from PCA demonstrated that some intermediate genotypes between XB and CWR were also found. Moreover, there were some genomic sequence changes including parental bands elimination and novel bands emergence in the ILs. The average Nei’s gene diversity (He) was 0.296, which was higher than that of cultivated rice. It suggested that interspecific hybridization and gene introgression could broaden the base of genetic variation and lay an important foundation for rice genetic improvement. These different genotypic ILs would provide a better experimental system for understanding the evolution of rice species and the mechanism of alien gene introgression.

Citrus Huanglongbing (HLB, yellow shoot disease) was first observed in the coastal Chaoshan Plain of Guangdong Province, China, in the late 19th century based on descriptions of yellow shoot symptoms. “Candidatus Liberibacter asiaticus” has been considered as a putative pathogen associated with HLB since 1994. Information about the curent prevalence of this bacterium is important for HLB control in Guangdong and also provides useful reference for HLB study elsewhere. In 2007, we collected HLB symptomatic citrus samples from 16 cultivars in 12 prefecture cities, mostly in the north and west regions of Guangdong, where major citrus fruits are currently produced. Among the 359 samples collected, 241 (67.1%) were positive for “Ca. L. asiaticus”, distributed in 15 out of the 16 cultivars from all 12 cities, indicating the widespread prevalence of “Ca. L. asiaticus” in Guangdong Province. The detection rates varied from 16.7 to 100% depending on location and cultivar. Lower detection rates were found in newer citrus cultivation cities among the previously less popular but now promoted cultivars. In reviewing the citrus management and pest control practice, we believe that infected nursery stocks play a key role in the current spread of “Ca. L. asiaticus”.

The red-flesh mutant Hong Anliu sweet orange is of high nutritional value due to its lycopene accumulation. Our previous studieson this mutant fruits suggested that photosynthesis and oxidative stress could promote the formation of mutation trait. However,leaf rather than fruit is the major part for some important biological processes such as photosynthesis. In this study, we analyzedthe proteomic alteration in leaves of the red-flesh mutant Hong Anliu vs. its wild type (WT). Ten differentially expressed proteinswere identified, of which two were involved in photosynthesis, three in oxidative stress, two in defense, and three in metabolism.The high up-regulation of photosynthetic proteins proved the hypothesis that enhanced photosynthesis could provide andtransport more substrates into mutant fruits for carotenoid biosynthesis. Similar to the previous results in fruits, anti-oxidativeproteins were highly up-regulated in leaves, suggesting the whole plant of Hong Anliu suffered from enhanced oxidative stressProteins involved in defense and metabolism were also identified, and their possible roles in the mutation were discussed.

WRKY transcription factors are involved in the regulation of response to biotic and abiotic stresses in plants. A fulllength cDNA clone of rice WRKY82 gene (OsWRKY82) was isolated from a cDNA library generated from leaves infected by Magnaporthe grisea. OsWRKY82 contained an entire open reading frame in length of 1 701 bp, and was predicted to encode a polypeptide of 566 amino acid residues consisting of two WRKY domains, each with a zinc finger motif of C₂H₂,belonging to the WRKY subgroup I. OsWRKY82 shared high identity at the amino acid level with those from Sorghum bicolor, Hordeum vulgare, and Zea mays. The transcript level of OsWRKY82 was relatively higher in stems, leaves, and flowers, and less abundant in grains. It was induced by inoculation with M. grisea and Rhizoctonia solani. However, the inducible expression in incompatible rice-M. grisea interactions was earlier and greater than that in compatible interactions.The expression of OsWRKY82 was up-regulated by methyl jasmonate and ethephon, whereas salicylic acid exerted no effects on its expression. Moreover, OsWRKY82 exhibited transcriptional activation ability in yeast. Additionally,OsWRKY82 transcripts could be induced by wounding and heat shocking, but not by abscisic acid, cold, high salinity and dehydration. By contrast, gibberellin suppressed the expression of OsWRKY82. These indicate that OsWRKY82 is a multiply stress-inducible gene responding to both biotic and abiotic stresses, and may be involved in the regulation of defense response to pathogens and tolerance against abiotic stresses by jasmonic acid/ethylene-dependent signaling pathway.