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Crapemyrtle bark scale (CMBS; Acanthococcus lagerstroemiae Kuwana), a fast-spreading invasive insect, has been causing damage to popular landscape plants in at least 17 states in the United States since 2004. This invasive insect has a list of documented plant hosts in ∼23 genera, which includes its primary hosts, crapemyrtles (Lagerstroemia spp.), as well as other important plant species, such as pomegranates, apple, and the native plant American beautyberry. Previous studies have shown CMBS causes different levels of feeding damage among its plant hosts, while the underlining plant defense mechanisms toward CMBS attacks remain elusive. A better understanding of plant–CMBS interactions and how CMBS performs under different plants (e.g., a susceptible vs. a resistant host) can provide valuable guidance for integrated pest management. Therefore, in this study, we conducted the age-stage, two-sex table study analysis to evaluate the biological parameters of CMBS on different species or cultivars of crapemyrtle under laboratory conditions (25 °C and 250 μmol·m−2·s−1 light with a photoperiod of 12 hours:12 hours (light:dark). Crapemyrtle bark scale development was found to be greatly influenced by the hosts. This study aims to provide important biological and ecological data on CMBS using a comprehensive life table study to gain a thorough understanding of its development, survival, and fecundity on different crapemyrtle species or cultivars.

Applications in biotechnology and synthetic biology often make use of soluble proteins, but there are many potential advantages to anchoring enzymes to a stable substrate, including stability and the possibility for substrate channeling. To avoid the necessity of protein purification and chemical immobilization, there has been growing interest in bio-assembly of protein-containing nanoparticles, exploiting the self-assembly of viral capsid proteins or other proteins that form polyhedral structures. But these nanoparticle are limited in size which constrains the packaging and the accessibility of the proteins. The axoneme, the insoluble protein core of the eukaryotic flagellum or cilium, is a highly ordered protein structure that can be several microns in length, orders of magnitude larger than other types of nanoparticles. We show that when proteins of interest are fused to specific axonemal proteins and expressed in living cells, they become incorporated into linear arrays which have the advantages of high protein loading capacity, high stability, and single-step purification with retention of biomass. The arrays can be isolated as membrane enclosed vesicle or as exposed protein arrays. The approach is demonstrated for both fluorescent proteins and enzymes, and in the latter case it is found that incorporation into axoneme arrays provides increased stability for the enzyme.

Crapemyrtle bark scale [CMBS (Acanthococcus lagerstroemiae)], a newly emerged pest in the United States, has spread to 16 U.S. states and unexpectedly spread on a native species american beautyberry (Callicarpa americana) in Texas and Louisiana in 2016 since it was initially reported on crapemyrtles (Lagerstroemia sp.) in Texas in 2004. The infestation of CMBS negatively impacted the flowering of crapemyrtles. We observed the infestation on the two most commercially available edible fig (Ficus carica) cultivars Beer’s Black and Chicago Hardy in a preliminary trial in 2018. To help estimate CMBS potential in aggravating risks to the ecosystem stability and the green industry, we conducted a host range and suitability test using ‘Bok Tower’ american beautyberry as a positive control with other eight beautyberry (Callicarpa) species [mexican beautyberry (C. acuminata), ‘Profusion’ bodinieri beautyberry (C. bodinieri), ‘Issai’ purple beautyberry (C. dichotoma), japanese beautyberry (C. japonica var. luxurians), ‘Alba’ white-fruited asian beautyberry (C. longissima), taiwan beautyberry (C. pilosissima), luanta beautyberry (C. randaiensis), and willow-leaf beautyberry (C. salicifolia)] and three fig (Ficus) species [creeping fig (F. pumila), roxburgh fig (F. auriculata), and waipahu fig (F. tikoua)] over 25 weeks. All the tested beautyberry species and waipahu fig sustainably supported the development and reproduction of nymphal CMBS and were confirmed as CMBS hosts. Furthermore, comparing with the control, mexican beautyberry, ‘Profusion’ bodinieri beautyberry, taiwan beautyberry, and willow-leaf beautyberry were significantly less suitable, while ‘Issai’ purple beautyberry, japanese beautyberry, ‘Alba’ white-fruited asian beautyberry, and luanta beautyberry were as suitable as ‘Bok Tower’ american beautyberry. Thus, when using beautyberries in landscapes, their different potential to host CMBS should be considered to minimize spreading CMBS through the native ecosystems.

Crapemyrtle bark scale (CMBS; Acanthococcus lagerstroemiae Kuwana) is an invasive insect that was first discovered in the United States in 2004. The polyphagous feeding habit of CMBS has allowed it to infest a wide range of plant species beyond its primary host, Lagerstroemia. Using molecular approaches, we studied the genetic relationships between CMBS specimens and their hosts from different geographic locations. Naturally occurring CMBS infestations were confirmed on American beautyberry (Callicarpa americana L.), a native plant species in the United States, and spirea (Spiraea L.). The new infestation of CMBS found on Spiraea raises the alarm that other economically important crops in the Amygdaloideae subfamily (subfamily under Rosaceae) might be susceptible to CMBS attacks.

Crapemyrtle bark scale (CMBS; Acanthococcus lagerstroemiae), an invasive sap-sucking hemipteran, has spread across 16 U.S. states. Infestation of CMBS negatively impacts the flowering of crapemyrtles and reduces the aesthetic quality of ornamental plants. The widespread use of soil-applied neonicotinoid insecticides to repress the CMBS infestation could threaten important beneficial insects; therefore, using natural enemies to control CMBS is greatly needed. This study evaluated larval green lacewing (Chrysoperla rufilabris) as a biocontrol agent of CMBS. Predatory behavior of the larval C. rufilabris upon CMBS was documented under a stereomicroscope using infested crapemyrtle samples collected from different locations in College Station. Predation potential of C. rufilabris upon CMBS eggs and foraging performance using Y-maze assay were both investigated in laboratory conditions. Results confirmed that larval C. rufilabris preyed on CMBS nymphs, eggs, and adult females. The evaluation of predation potential results showed that the number of CMBS eggs consumed in 24 hours by 3rd instar C. rufilabris (176.4 ±6.9) was significantly higher than by 2nd instar (151.5±6.6) and by 1st instar (11.8±1.3). The foraging performance results showed that larval C. rufilabris could target CMBS under dark, indicating that some cues associated with olfactory response were likely involved when preying on CMBS. This study is the first report that validated C. rufilabris as a natural predator of CMBS and its potential as a biological agent to control CMBS. Future investigation about the olfactory response of larval C. rufilabris to CMBS would benefit the development of environmental-friendly strategies to control CMBS spread.

Three-dimensional printing of hydrogel constructs containing algae cells, also known as green bioprinting, has many potential applications. Its feasibility has been demonstrated for removing metal contaminants in water and tissue engineering. However, in reported studies on green bioprinting so far, shape fidelity was either not investigated or poor. This paper reports a study to apply layer-by-layer photo-crosslinking in extrusion-based 3D printing of constructs using gelatin methacryloyl (GelMA) bioink containing Chlamydomonas reinhardtii algae cells. Shape fidelity and cell viability are compared between constructs printed by applying layer-by-layer photo-crosslinking and those printed by applying once-post-printing photo-crosslinking. Comparisons of shape fidelity are also made with alginate-methylcellulose constructs printed by applying ionic-crosslinking. Results show that GelMA constructs printed by applying layer-by-layer photo-crosslinking have the highest shape fidelity among all printed constructs, and about three-quarters of the algae cells in all printed GelMA constructs are alive four days post-printing. There are no significant differences in cell viability between the GelMA constructs printed by applying layer-by-layer photo-crosslinking and the GelMA constructs printed by applying once-post-printing photo-crosslinking.

Microalgae can be part of the solution to the global food crisis, as they have high nutritional values. Recently, 3D printing of microalgae-enriched snacks has been reported with the capability to customize nutritional profiles, shapes, and textures of the snacks. Because the process parameters of extrusion-based 3D printing affect the printability of cookie dough, it is important to know the levels of process parameters leading to continuous extrusion. This study investigated feasible regions of printing process parameters for continuous extrusion of microalgae (Arthrospira Platensis) enriched cookie dough. The process parameters studied were nozzle diameter, printing speed, and air pressure. The feasible regions were determined by visual inspections of printed strands. The results show that, for smaller nozzle diameters and higher printing speeds, higher air pressures are required to ensure continuous extrusion. The identified feasible regions from this study would be helpful when deciding the appropriate nozzle diameter, printing speed, and air pressure to print microalgae-enriched cookie dough and other materials with similar rheological properties in extrusion-based 3D printing.

This review discusses the reported studies investigating the use of bioprinting to develop functional organ-on-chip systems from a manufacturing perspective. These organ-on-chip systems model the liver, kidney, heart, lung, gut, bone, vessel, and tumors to demonstrate the viability of bioprinted organ-on-chip systems for disease modeling and drug screening. In addition, the paper highlights the challenges involved in using bioprinting techniques for organ-on-chip system fabrications and suggests future research directions. Based on the reviewed studies, it is concluded that bioprinting can be applied for the automated and assembly-free fabrication of organ-on chip systems. These bioprinted organ-on-chip systems can help in the modeling of several different diseases and can thereby expedite drug discovery by providing an efficient platform for drug screening in the preclinical phase of drug development processes.

Summary The sensory organelle cilium is involved in sensing and transducing important signaling cascades in almost all cells of our body. These ciliary-mediated pathways affect cellular homeostasis and metabolisms profoundly. However, it is almost completely unknown whether the cellular metabolic state affects the assembly of cilia. This study is to investigate how O-linked β-N-acetylglucosamine (O-GlcNAc), a sensor of cellular nutrients, regulates the cilia length. Pharmacologic or genetic inhibition of O-GlcNAcylation led to longer cilia, and vice versa. Further biochemical assays revealed that both α-tubulin and HDAC6 (histone deacetylase 6) were O-GlcNAcylated in vivo. In vitro enzymatic assays showed that O-GlcNAcylation of either tubulin or HDAC6 promoted microtubule disassembly, which likely in turn caused ciliary shortening. Taken together, these results uncovered a negative regulatory role of O-GlcNAc in modulating the ciliary microtubule assembly. The cross talk between O-GlcNAc and cilium is likely critical for fine-tuning the cellular response to nutrients., Graphical Abstract, Highlights • Cellular O-GlcNAc level inversely regulates ciliary length • Attenuated O-GlcNAc level increases the percentage of ciliated cells in hTERT-RPE1 • O-GlcNAcylation of α-tubulin promotes ciliary axoneme disassembly • O-GlcNAcylation of HDAC6 promotes its deacetylase activity, Biological Sciences; Molecular Biology; Cell Biology; Functional Aspects of Cell Biology

Copper contamination of drinking water and marine areas is detrimental to human health and the environment. Physical and chemical approaches currently used for copper removal from water tend to be expensive and may introduce chemicals to the water. Using suspended algae to remove copper is a biological approach. Its cost is relatively low, and algae can be used for other purposes after being used for copper removal. However, this approach using algae is currently limited in its usefulness due to technological barriers. For example, chemical agents used to remove suspended algae from water after copper is absorbed can cause secondary contamination. Using immobilized algae instead of suspended algae can overcome these problems. In this preliminary study, hydrogel filters containing algae cells and those containing no algae cells are printed on an extrusion-based 3D printer. They were used in a custom-build filtration setup for copper removal. Experimental results show that hydrogel filters containing algae cells reduced copper concentration in the test solution by about 83% (from 3 to 0.5 ppm) after 1 h of filtration, while hydrogel filters containing no algae cells reduced copper concentration in the test solution by about 50% (from 3 to 1.5 ppm) after 1 h of filtration.

Crapemyrtle bark scale (CMBS, Acanthococcus lagerstroemiae), an invasive polyphagous sap-sucking hemipteran, has spread across 14 states of the United States since 2004. The infestation of CMBS has negatively impacted the flowering of ornamental plants and even the fruiting of some crops. Host identification is critical for determining potential risks in ecosystems and industries and helps develop strategic management. A host confirmation test was performed over 25 weeks using six Lagerstroemia species (L. caudata, L. fauriei &lsquo, Kiowa&rsquo, L. indica &lsquo, Dynamite&rsquo, L. limii, L. speciosa, and L. subcostata) and California loosestrife (Lythrum californicum). The 25-week observations confirmed all tested plants as the hosts. The repeated measures of analysis of variance (ANOVA, Tukey&rsquo, s HSD, &alpha, = 0.05) indicated that the average number of CMBS females differed significantly between L. limii and L. speciosa. The highest number of the females observed on L. limii was 576 &plusmn, 25 (mean &plusmn, SE) at 17 weeks after inoculation (WAI), while the highest number was 57 &plusmn, 15 on L. speciosa at 19 WAI. In addition, L. subcostata and L. speciosa had significantly high and low numbers of males, respectively, among the Lagerstroemia species. Our results suggest that L. speciosa could be incorporated in developing new cultivars with low CMBS suitability.

Bioprinting is the fabrication of structures based on layer-by-layer deposition of biomaterials. Applications of bioprinting using plant or algae cells include the production of metabolites for use in pharmaceutical, cosmetic, and food industries. Reported studies regarding effects of extrusion pressure and needle diameter on cell viability in bioprinting have used animal cells. There are no reports regarding effects of extrusion pressure and needle diameter on cell viability using plant or algae cells. This paper fills this knowledge gap by reporting an experimental investigation on effects of extrusion pressure and needle diameter on cell quantity (an indicator of cell viability) in extrusion-based bioprinting of hydrogel-based bioink containing Chlamydomonas reinhardtii algae cells. Extrusion pressure levels used in this study were 3, 5, and 7 bar, and needle diameter levels were 200, 250, and 400 µm. Algae cell quantity in printed samples was measured on the third day and sixth day post bioprinting. Results show that, when extrusion pressure increases or needle diameter decreases, algae cell quantity in printed samples decreases.

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Bioprinting has many potential applications in drug screening, tissue engineering, and regenerative medicine. In extrusion-based bioprinting, the extruded strand is the fundamental building block for printed constructs and needs to be of good quality and continuous in structure. In recent years, many studies have been conducted on extrusion-based bioprinting. However, values of process parameters leading to continuous extrusion of strands have rarely been reported. In this paper, feasible regions of bioink composition, extrusion pressure, and needle size for continuous strand extrusion have been evaluated. The information on feasible regions for extruding continuous strands, provided in this paper, can be useful in deciding appropriate extrusion pressure and needle size for the bioink of different compositions (ratios of alginate:methylcellulose) in extrusion-based bioprinting.

In bioprinting, biomaterials are deposited layer-by-layer to fabricate structures. Bioprinting has many potential applications in drug screening, tissue engineering, and regenerative medicine. Both animal cells and plant cells can be used to synthesize bioinks. Green bioprinting uses bioinks that have been synthesized using plant cells. Constructs fabricated via green bioprinting contain immobilized plant cells, with these cells arranged at desired locations. The constructs provide scaffolds for cell growth. Printing parameters affecting the growth of cells in green bioprinted constructs include print speed, needle diameter, extrusion temperature, and extrusion pressure. This paper reports a study to examine effects of extrusion pressure on cell growth (measured by cell count) in bioprinted constructs, using bioink containing Chlamydomonas reinhardtii algae cells. Three levels of extrusion pressure were used: 3, 5, and 7 bar. Cell counts in the bioprinted constructs were measured on the third and sixth days after bioprinting. It was found that, as extrusion pressure increased, cell count decreased on both the third and sixth days after bioprinting. Furthermore, the difference in cell counts between the third and the sixth days decreased as extrusion pressure increased. These trends suggest that increasing extrusion pressure during green bioprinting negatively affects cell growth. A possible reason for these trends is physical damage to or death of cells in the bioprinted constructs when extrusion pressure became higher.

Bioprinting technology has a great potential in the fields of tissue engineering and regenerative medicine. In tissue engineering, for a bioprinted tissue to be successful in supporting regeneration of new tissue, it should morphologically mimic the native tissue in vivo. Therefore, the bioprinted tissue needs to be dimensionally accurate. In extrusion-based bioprinting, 3D printing process parameters and bioink properties affect dimensional accuracy of printed constructs. Currently, little information is available on effects of bioink composition and printing direction on dimensional accuracy of 3D printed constructs using alginate:methylcelluolose based bioink. In this study, strands were printed using four compositions of alginate:methylcellulose bioink and two printing directions. The four compositions of alginate:methylcellulose bioink were 1:1.5, 1:2, 1:2.5 and 1:3, and the two printing directions were vertical and horizontal. The statistical analysis of strand width measurement data revealed that while bioink composition has significant effect, printing direction does not affect the strand width of 3D printed constructs at the significance level of 0.05.

Bioprinting can fabricate structures based on layer-by-layer deposition of biomaterials. Bioprinting of animal cells shows great promise for tissue regeneration and tissue research. Plant cells can also be used when synthesizing bioink. Bioprinting with bioink that has been synthesized with plant cells instead of animal cells is called green bioprinting. Green bioprinting offers greater spatial control over the growth of plant matter by immobilizing cells. It is known that certain variables affect the growth and propagation (cellular reproduction) of cells in green bioprinted constructs post bioprinting. These variables include accessibility to components required for photosynthesis, such as nutrients, moisture and light. However, multiple parameters can also vary during the extrusion of bioink in the bioprinting process, including extrusion pressure, extrusion temperature, needle diameter, and printing speed. This paper reports a study to examine the effects of needle diameter during bioprinting on the growth of Chlamydomonas reinhardtii algae cells in green bioprinted constructs. Growth of Chlamydomonas reinhardtii algae cells was quantified by measuring cell count. The constructs were bioprinted with needle diameters of 22 gauge, 25 gauge, and 27 gauge. It was found that decreasing needle diameter was correlated with decreased cell count on the second and fifth days post bioprinting. Furthermore, the magnitude of cell count increase between the second and the fifth days post bioprinting decreased with decreasing needle diameter. Future research is needed to examine the effects of other printing parameters on cell growth.

Drinking water contaminated with metal ions can cause negative health effects in humans. Acute heavy metal poisoning can cause such symptoms as vomiting and fainting, while chronic heavy metal poisoning can lead to organ failure and death. It has previously been shown that concentration of metal ions in water solution was decreased by algae. This paper reports a study to examine the ability of two Chlamydomonas reinhardtii algae strains to remove copper ions from water solution. Chlamydomonas reinhardtii was chosen for this study because it is easy to culture, and can be used to generate strains with a higher efficiency to remove metals. In this study, the three-factor, two-level full factorial design was used to conduct experiments. Three factors were algae strain, initial copper concentration, and exposure time. Two levels of the algae strain are: cc125 — the Chlamydomonas reinhardtii strain found commonly in the wild, and AGG1 — an experimentally modified Chlamydomonas reinhardtii strain. Two levels of initial copper concentration and exposure time were 1.5 and 3 ppm, and 2.5 and 5 hours, respectively. Copper concentration in the water solution after experiments was measured using inductively coupled plasma-mass spectrometry, or ICP-MS. Statistical analysis showed that algae strain was the only factor that significantly affected percentage decrease in copper concentration, at the significance level of 0.05. The cc125 strain decreased copper concentration more efficiently than the AGG1 strain. The cc125 strain decreased copper concentration by 97% for the water solution with an initial copper concentration of 1.5 ppm, and by 90% for the solution with an initial copper concentration of 3 ppm. Copper concentrations of all solutions treated by the cc125 strain were below the Environmental Protection Agency pollution threshold level of 1.3 ppm.

In extrusion-based bioprinting, 3D printing process parameters affect dimensional accuracy of printed constructs. However, little information is currently available on effects of extrusion temperature and printing direction on dimensional accuracy of 3D printed constructs using Alginate:Methylcelluolose hydrogel. In this study, strand thickness of 3D printed constructs printed at temperature of 35°C, 40°C, 45°C and at vertical and horizontal printing direction were measured. The statistical analysis revealed that extrusion temperature and printing direction have significant effect on the strand thickness of 3D printed constructs.

Flagellar length control in Chlamydomonas is a tractable model system for studying the general question of organelle size regulation. We have previously proposed that the diffusive return of the kinesin motor that powers intraflagellar transport can play a key role in length regulation. Here, we explore how the motor speed and diffusion coefficient for the return of kinesin-2 affect flagellar growth kinetics. We find that the system can exist in two distinct regimes, one dominated by motor speed and one by diffusion coefficient. Depending on length, a flagellum can switch between these regimes. Our results indicate that mutations can affect the length in distinct ways. We discuss our theory's implication for flagellar growth influenced by beating and provide possible explanations for the experimental observation that a beating flagellum is usually longer than its immotile mutant. These results demonstrate how our simple model can suggest explanations for mutant phenotypes.

We describe an approach for using the flagella axoneme as the basis for biological self-assembling protein nanoarrays. The axoneme is the insoluble protein core of the eukaryotic flagellum or cilium. By attaching a protein of interest to particular axonemal proteins, it is possible to exploit the intraflagellar transport system to incorporate those proteins into the axoneme as it assembles. Using the axoneme as a protein array confers several advantages, such as high protein loading capacity compared to other bioparticle systems; genetically programmed self-assembly without the need for any linking steps; single-step purification of particles without the need for cell lysis, allowing retention and re-use of biomass; and choice of isolating the particle as a membrane enclosed vesicle or as an exposed protein array. Here we test several potential axonemal proteins as adaptor proteins, using green fluorescent protein as a test case. We find that FAP20 is an ideal scaffold protein for this purpose in that it shows high incorporation and uniform localization. We verify that FAP20-GFP constructs are stably associated with the axoneme during purification and storage, that the GFP moiety can be released by protease cleavage, and that the flagellar array can be easily encapsulated in aqueous-oil emulsion droplets for use in microfluidic assays.

Although microtubules are known for dynamic instability, the dynamicity is considered to be tightly controlled to support a variety of cellular processes. Yet diverse evidence suggests that this is not applicable to Chlamydomonas, a biflagellate fresh water green alga, but intense autofluorescence from photosynthesis pigments has hindered the investigation. By expressing a bright fluorescent reporter protein at the endogenous level, we demonstrate in real time discreet sweeping changes in algal microtubules elicited by rises of intracellular H+ and Na+. These results from this model organism with characteristics of animal and plant cells provide novel explanations regarding how pH may drive cellular processes; how plants may respond to, and perhaps sense stresses; and how organisms with a similar sensitive cytoskeleton may be susceptible to environmental changes.

The microtubule cytoskeletal system is integral to diverse cellular processes. Although microtubules are known for dynamic instability, the system is tightly controlled in typical interphase animal cells. In contrast, diverse evidence suggests that the system is mercurial in the unicellular fresh water green alga,Chlamydomonas, but intense autofluorescence from photosynthesis pigments has hindered the investigation. By expressing a bright fluorescent reporter protein at the endogenous level, we demonstrate in real time discreet sweeping changes in algal microtubules elicited by fluctuation of intracellular H+and Na+. These results suggest disparate sensitivity of this vital yet delicate system in diverse organisms; and illuminate how pH may drive crucial cellular processes; how plants respond to, and perhaps sense stresses; and how many species could be susceptible to accelerated changes in global environments.

Intraflagellar transport (IFT) is essential for the assembly and maintenance of flagella and cilia. Recent biochemical studies have shown that IFT complex B (IFT-B) is comprised of two subcomplexes, IFT-B1 and IFT-B2. The IFT-B2 subunit IFT57 lies at the interface between IFT-B1 and IFT-B2. Here, using a Chlamydomonasreinhardtii mutant for IFT57, we tested whether IFT57 is required for IFT-B complex assembly by bridging IFT-B1 and IFT-B2 together. In the ift57-1 mutant, levels of IFT57 and other IFT-B proteins were greatly reduced at the whole-cell level. However, strikingly, in the protease-free flagellar compartment, while the level of IFT57 was reduced, the levels of other IFT particle proteins were not concomitantly reduced but were present at the wild-type level. The IFT movement of the IFT57-deficient IFT particles was also unchanged. Moreover, IFT57 depletion disrupted the flagellar waveform, leading to cell swimming defects. Analysis of the mutant flagellar protein composition showed that certain axonemal proteins were altered. Taken together, these findings suggest that IFT57 does not play an essential structural role in the IFT particle complex but rather functions to prevent it from degradation. Additionally, IFT57 is involved in transporting specific motility-related proteins.

Mediating the transport of flagellar precursors and removal of turnover products, intraflagellar transport (IFT) is required for flagella assembly and maintenance. The IFT apparatus is composed of the anterograde IFT motor kinesin II, the retrograde IFT motor IFT-dynein, and IFT particles containing two complexes, A and B. In order to have a balanced two-way transportation, IFT-dynein has to be carried into flagella and transported to the flagellar tip by kinesin II, where it is activated to drive the retrograde IFT back to the flagellar base. In this study, we investigated the role of complex A and complex B in the flagellar entry and exit of IFT-dynein. We showed that regardless of the amount of complex A, IFT-dynein accumulated proportionally to the amount of complex B in the flagella of fla15/ift144 and fla17-1/ift139, two complex A temperature-sensitive mutants. Complex A was depleted from both cellular and flagellar compartments in fla15/ift144 mutant. However, in fla17-1/ift139 mutant, the flagellar level of complex A was at the wild-type level, which was in radical contrast to the significantly reduced cellular amount of complex A. These results support that complex A is not required for the flagellar entry of IFT-dynein, but might be essential for the lagellar exit of IFT-dynein. Additionally, we confirmed the essential role of IFT172, a complex B subunit, in the flagellar entry of IFT-dynein. These results indicate that complexes A and B play complementary but distinct roles for IFT-dynein, with complex B carrying IFT-dynein into the flagella while complex A mediates the flagellar exit of IFT-dynein.