Dataset Information

Effect of Essential Nutrients on Roots Growth and Lifespan of Huanglongbing Affected Citrus Trees.

ABSTRACT: Understanding citrus tree root development and dynamics are critical in determining crop best nutrient management practices. The role of calcium (Ca) and magnesium (Mg), manganese (Mn), Zinc (Zn), and boron (B) on huanglongbing (HLB) affected citrus trees' root growth and lifespan in Florida is not fully documented. Thus, the objective of this study was to determine the impact of foliar and ground-applied essential nutrients on seasonal fine root length density (FRLD; diameter (d) < 2 mm) and coarse roots (d > 2 mm), FRLD dynamics, root survival probability (lifespan), and root-zone soil pH of HLB-affected sweet orange trees. Results indicated that Ca treated trees budded on Cleopatra (Cleo) and Ca and Mg combined treatments on Swingle (Swc) rootstocks significantly increased seasonal FRLD of fine (< 2 mm) and coarse roots. The highest median root lifespan of Ca treated trees was 325 and 339 days for trees budded on Cleo and Swc rootstocks, respectively. In the second study, the coarse roots showed a significantly higher reaction to the nutrition applied than the fine roots. Meanwhile, the 2× (1× foliar and 1× ground-applied) treated trees showed a significantly higher median root lifespan compared to the other treatments. Thus, the current study unwraps future studies highlighting the combined soil and/or foliar application of the above nutrients to stimulate FRLD and improve root lifespan on HLB-affected sweet oranges with emphasis on root-zone soil pH.

SUBMITTER: Atta AA

PROVIDER: S-EPMC7238226 | biostudies-literature | 2020 Apr

REPOSITORIES: biostudies-literature

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Effect of Essential Nutrients on Roots Growth and Lifespan of Huanglongbing Affected Citrus Trees.

Atta Alisheikh A AA Morgan Kelly T KT Hamido Said A SA Kadyampakeni Davie M DM

Plants (Basel, Switzerland) 20200409 4

Understanding citrus tree root development and dynamics are critical in determining crop best nutrient management practices. The role of calcium (Ca) and magnesium (Mg), manganese (Mn), Zinc (Zn), and boron (B) on huanglongbing (HLB) affected citrus trees' root growth and lifespan in Florida is not fully documented. Thus, the objective of this study was to determine the impact of foliar and ground-applied essential nutrients on seasonal fine root length density (FRLD; diameter (d) < 2 mm) and co ...[more]

PMID: 32283776

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Project description:Citrus production under enclosed structures can exclude the Asian citrus psyllid (ACP, Diaphorina citri) and eliminate the negative effects of citrus greening or huanglongbing (HLB) disease caused by Candidatus Liberibacter asiaticus to the grapefruit (Citrus paradisi) fresh fruit industry. Physically impeding the insect vector from accessing trees is a logical method to have disease-free groves. Our objectives were to assess the ability of enclosed screenhouses to exclude the ACP, stop HLB inoculation and dissemination, and improve fruit yield of in-ground and container-grown 6-year-old "Ray Ruby" grapefruit at super-high planting densities relative to open-air trees. We built a large structure to allow commercial-scale trials and tested two production systems (screenhouse and open-air), two planting systems (in-ground and potted), and two rootstocks ("Sour Orange" [Citrus × aurantium] and "US-897" [Citrus reticulata × Poncirus trifoliate]). The experimental design was a randomized complete block design split-split-plot with four replications. Four passively ventilated 1,080-m2 completely enclosed screenhouses were constructed using a 50-mesh monofilament high-density polyethylene screen. The main support for each enclosed, covered structure consisted of pressure-treated, wooden utility poles. Trees were planted in Sept/2013 on a density of 1,957 trees/ha. Irrigation was performed on-demand using two 7.6-LPH drip emitters per tree, and fertigation was applied three times/week using 15N-2.6P-22.4K water-soluble fertilizer at 180 kg N/ha. Psyllids were monitored using sticky cards and detected inside the screenhouses post-Hurricane Irma, which damaged the screen structures in Sept/2017, leaving openings until repairs were completed in Apr/2018. Screen aging and a tropical storm in April/2019 caused another major screen opening fixed in Oct/2019. Despite the weather-related damages to the screens, only trees cultivated in open-air tested positive for Candidatus Liberibacter asiaticus after 6 years. There was fast disease progression for all outside treatments, with 100% infection. Covered, in-ground trees exhibited the highest trunk diameter and canopy volume (P < 0.0001). Trees grown inside screenhouses exhibited higher fruit yield than outside trees, with the highest yield observed for in-ground trees on "US-897" (51,081 kg/ha) (P < 0.0001). Several open-air treatments particularly in containers did not produce any fruit. On the other hand, potted grapefruit trees cultivated inside the enclosures had the highest soluble solids content (P < 0.001). The screenhouses provided disease exclusion, increased fruit yield, and fruit quality, representing an alternative for growers interested in producing high-quality fruit for the fresh market. Production cost and economic viability still need to be evaluated for large-scale implementation.

Project description:In this data set, we reported for the first time that huanglongbing disease (HLB) induces major changes in the expression of global genes in flavedo, vascular and juice vesicle tissues of citrus fruit. 68 Total samples were analyzed. cDNA generation, array analysis, and statistical tests were performed as a service at the Interdisciplinary Center for Biotechnology Research (ICBR) Microarray Core facility at the University of Florida (Gainesville, FL). The linear models were used for array analysis (Smyth GK et al. Bioinformatics, 2005, 2067-2075). The linear models were firstly used to assess differential expression, and then an empirical Bayes method was used to moderate the standard errors. 13 comparisons were performed for the study. The comparisons in Citrus sinensis cv. Hamlin included: SC vs. CC (genes that respond to infection in symptomatic vascular core); SJV vs. CJV (genes that respond to infection in symptomatic juice vesicle); SS vs. CS (genes that respond to infection in symptomatic seed); SP vs. CP (genes that respond to infection in symptomatic peel). The comparisons in Citrus sinensis cv. Valencia included: SP vs. HP (genes that respond to infection in symptomatic peel); ASP vs. HP (genes that respond to infection in asymptomatic peel); SP vs. ASP (genes that respond to infection in symptomatic peel compared to asymptomatic peel); SC vs. HC (genes that respond to infection in symptomatic vascular core); ASC vs. HC (genes that respond to infection in asymptomatic vascular core); SC vs. ASC (genes that respond to infection in symptomatic vascular core compared to asymptomatic vascular core); SJV vs. HJV (genes that respond to infection in symptomatic juice vesicle); ASJV vs. HJV (genes that respond to infection in asymptomatic juice vesicle); SJV vs. ASJV (genes that respond to infection in symptomatic juice vesicle compared to asymptomatic juice vesicle). ESTs with significant expression changes (P value <0.001; false discovery rate <0.01 with equal or higher than 2-fold changes in expression) were selected for further analysis.

Project description:BACKGROUND:Citrus blight is a very important progressive decline disease of commercial citrus. The etiology is unknown, although the disease can be transmitted by root grafts, suggesting a viral etiology. Diagnosis is made by demonstrating physical blockage of xylem cells that prevents the movement of water. This test was used to identify symptomatic trees from four commercial groves in Florida. Total RNA extracts of phloem-enriched scaffold root tissues were prepared from seven trees that failed to take up water and from one healthy tree. These RNA extracts were used for transcriptomic analyses using paired end RNA-Seq from an Illumina 2500 system. The expression of transcripts annotated as polyprotein of citrus endogenous pararetrovirus were estimated by both RT-qPCR and RNA-Seq. RESULTS:Transcripts from seven RNA-Seq libraries from trees affected by citrus blight were compared to a control tree. 129-148 million RNA fragments (two paired-end reads/fragment) were generated per library and were mapped to the sweet orange reference genome. In response to citrus blight stress, genes encoding aquaporins, proteins with water channel activity and several cellulose synthase genes were down-regulated, whereas genes involved in lignin and glucosinolate biosynthesis were up-regulated. Transcripts encoding proteins in pathways of carbohydrate metabolism, nucleotide synthesis, signaling, hormone metabolism, secondary metabolism, transport, and biotic stress pathways were overwhelmingly down regulated in all libraries. CONCLUSION:Reduced water intake and xylem plugging were observed in the trees tested and the changes in their transcriptome were analyzed. Plants adapted to reduced water flow by regulating primary and secondary metabolism, nuclear transport and hormone associated pathways. The patterns of energy generation, transcription, translation and protein degradation were consistent with irreversible decline. The down regulation of cellulose synthase transcripts and up regulation of transcripts related to lignin production likely lead to an imbalance in the pathways leading to wood formation, and may lead to the blockage of the xylem vessels seen as the cardinal symptom of citrus blight. Transcripts of a pararetrovirus were elevated in the transcriptome of roots used in this study.

Project description:The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama, is the key pest of citrus wherever it occurs due to its role as vector of huanglongbing (HLB) also known as citrus greening disease. Insecticidal vector control is considered to be the primary strategy for HLB management and is typically intense owing to the severity of this disease. While this approach slows spread and also decreases severity of HLB once the disease is established, economic viability of increasingly frequent sprays is uncertain. Lacking until now were studies evaluating the optimum frequency of insecticide applications to mature trees during the growing season under conditions of high HLB incidence. We related different degrees of insecticide control with ACP abundance and ultimately, with HLB-associated yield losses in two four-year replicated experiments conducted in commercial groves of mature orange trees under high HLB incidence. Decisions on insecticide applications directed at ACP were made by project managers and confined to designated plots according to experimental design. All operational costs as well as production benefits were taken into account for economic analysis. The relationship between management costs, ACP abundance and HLB-associated economic losses based on current prices for process oranges was used to determine the optimum frequency and timing for insecticide applications during the growing season. Trees under the most intensive insecticidal control harbored fewest ACP resulting in greatest yields. The relationship between vector densities and yield loss was significant but differed between the two test orchards, possibly due to varying initial HLB infection levels, ACP populations or cultivar response. Based on these relationships, treatment thresholds during the growing season were obtained as a function of application costs, juice market prices and ACP densities. A conservative threshold for mature trees with high incidence of HLB would help maintain economic viability by reducing excessive insecticide sprays, thereby leaving more room for non-aggressive management tools such as biological control.

Dataset Information

Effect of Essential Nutrients on Roots Growth and Lifespan of Huanglongbing Affected Citrus Trees.

Publications

Effect of Essential Nutrients on Roots Growth and Lifespan of Huanglongbing Affected Citrus Trees.

Similar Datasets

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