The inoculation of upland rice with multifunctional microorganism significantly affected the root (Fig. 1A) and shoots (Fig. 1B) developments. The inoculation of combined Phanerochaete australis (BRM 62389) + Serratia marcenscens (BRM 32114), treatment 27, led to the highest percentage increase in the root weight of upland rice (19.4 grams), though values did not differ from root weight recorded in upland rice plants treated with Azospirillum sp. (BRM 63574) + BRM 32110, treatment 19 (18.58 grams), Bacillus sp. (BRM 63573) + A. brasilense (AbV5), treatment 16 (18.65 grams) and P. australis (BRM 62389) + B. toyonensis (BRM 32110), treatment 28 (18.48 grams). On the other hand, a significantly lower root weight by 8.23 g was observed for upland rice in the control plants. Also Sousa et al. (2019), in lowland rice, and Fernandes et al. (2020), in upland rice, reported increases in root development when using beneficial microorganisms in relation to the control plants (no microorganisms). According to Filippi et al. (2011), multifunctional microorganisms can control harmful microorganisms by producing antibiotics and enzymes that degrade the cell wall, favoring the root development of plants. Besides, these microorganisms produce indol acetic acid (Nascente et al., 2017a, 2017b) a phytohormones that provide better root development. This better root development can contribute to improve the achievement of water and nutrients and allow increasing shoot development, as observed in our trial (Fig. 1B). In addition, we could see that the use of the coinoculations P. australis (BRM 62389) + S. marcenscens (BRM 32114), Azospirillum sp. (BRM 63574) + B. toyonensis (BRM 32110) and Bacillus sp. (BRM 63573) + A. brasilense (AbV5) provided increase in the root development when compared to the single microorganisms S. marcescens, B. toyonensis, P. australis, T. koningiopsis, A. brasilense, Azospirillum sp and Bacillus sp. Therefore, we can infer that the effect of the coinoculation was better than the use of single microorganisms, in root and shoot development.
Upland rice shoots weight was recorded as highest when rice seeds were treated with treatment 16 (32.78 grams), Bacillus sp. (BRM 63573) + A. brasilense (AbV5) (Fig. 1B). Similar effect was observed in treatment 19 (32.38 grams), with Azospirillum sp. (BRM 63574) + B. Toyonensis (BRM 32110) and treatment 27 (31.75 grams), BRM 62389 + BRM 32114 treated plants. In the same way as in the roots, shoots development was higher in coinoculation when compared to the sole microorganisms. Cruz et al. (2023) also reported significant increases in corn shoots in treatments with microorganisms in comparison to untreated plants. They reported that plants with high developed root system can translocate more nutrients and improve shoot development.
The highest number of panicles of upland rice was obtained in treatment 19 (15 panicles per pot), with the B. toyonensis (BRM 32110) + Azospirillum sp. (BRM 63574) and did not differed from 3 (13,75 panicles per pot), P. australis (BRM62389), 12 (14 panicles per pot), B. toyonensis (BRM 32110) + T. koningiopsis (BRM 53736), 16 (13,50 panicles per pot), Bacillus sp. (BRM 63573) + A. brasilense (AbV5) and M27 (14.5 panicles per pot), BRM 62389 + BRM 32114 (Fig. 2A). This result could be attributed to the fact that Azospirillum and other microorganisms can assist in plant growth through nitrogen fixation, and produces other phytoregulators such as abscisic acid, cytokinins, gibberellins, ethylene and polyamines (Cassán and DiazZorita 2016). Besides, the ability of beneficial microorganisms to produce siderophores and solubilize phosphate could have led to greater availability of iron and phosphorus in the soil solution and provide better conditions to improve panicle formation in upland rice (Goswami et al. 2016; Kumar et al. 2021). Podile and Kishore (2006) reported that the most potent phosphate solubilizers belong to the genera of Bacillus, Enterobacter, Erwinia, and Pseudomonas. Rhizospheric bacteria such as Bacillus secrete siderophores which are low molecular weight iron chelators having an affinity for complex iron (Ansari et al. 2017). Nascente et al. (2017a, b) also reported increases in upland and lowland rice development with the use of microorganisms, such as BRM 32114 and BRM 32110.
A significant increase in number of panicles per pot with coinoculation of the best combinations of microorganisms was recorded relative to sole S. marcescens, B. toyonensis, T. koningiopsis, A. brasilense, Azospirillum sp, Bacillus sp treated plants and the control (Fig. 2A). Number of panicles is the most important yield component and therefore, significantly affect grain yield (Nascente et al., 2013).
The highest value for number of grains per pot of upland rice was obtained with treatment 26 (141.43 grains per pot) (P. australis + T. koningiopsis), which was similar to the values obtained from the treatments 16 (132.23 grains per pot) (Bacillus sp. BRM 63573 + A. brasilense AbV5) and 14 (134.18 grains per pot) (Bacillus sp. BRM 63573 + Azospirillum sp. BRM 63574), but higher than the value obtained from the control treatment and significantly different from all other treatments (Fig. 2B). The enhanced number of grain per pot reported in P. australis + S. marcenscens could be attributed to the ability of the combined microorganism to fix nitrogen, solubilize P, produce biofilm and cyanide as observed in their biochemical characteristics relative to other microorganism treated pot (Nascente et al. 2017a). Besides, the inoculation of upland rice with combination of P. australis BRM 62389 + T. koningopsis BRM 53736 led to 61% increase in number of grains per pots of upland rice relative the control. In addition, an increase of 45.0 g, 37.1 g, 35.7 g, 45.1 g, 64.8 g, 33.8 g, 55.3 g was observed for number of grains per pot of rice treated with P. australiani BRM 62389 + T. koningopsis BRM 53736 relative to sole microorganisms of S. marcescens, B. toyonensis, P. australis, T. koningiopsis, A. brasilense, Azospirillum sp and Bacillus sp., respectively.
The treatments of upland rice with sole and combined microorganism significantly affected the mass of 1000 grains (Fig. 2C). This could be attributed to increase roots and shoots size provided by the multifunctional microorganism (Alvarez et al. 2012). Multifunctional microorganisms can promote better development of the plants with direct effect on the size of the grain and in the grain yield (Pereira et al. 2020). The improvement in the size of rice grains is important once it can provide increases in the quality and in the final price received by the farmers (Bordin et al. 2014). Araujo et al. (2021) that worked with multifunctional microorganisms on upland rice plants reported bigger sizes of the grains in plants treated than untreated. The treatments 16, BRM 63573 Bacillus sp + A. brasilense AbV5 (38.72 grams), 19, Azospirillum sp BRM 63574 + B. toyonensis BRM 32110 (38.02 grams) and 27 with P. australiani BRM 62389 + S. marcenscens BRM 32114 (36.7 grams) produced similar values of mass of 1000 grains, which was significantly higher than the values obtained from all other treated plants and control pots. The inoculation of upland rice with combination of BRM 63573 Bacillus sp + AbV5 A. brasilense led to 27% increase in 1000 grains weight of upland rice relative the control. In addition, an increase of 7.86 g, 6.47 g, 6.5 g, 7.98 g, 12.47 g, 5.65 g, and 10.36 g was observed for mass of 1000 grains weight of rice treated with Bacillus sp BRM 63573 + AbV5 A. brasilense, relative to sole microorganisms of S. marcescens, B. toyonensis, P. australis, T. koningiopsis, A.brasilense, Azospirillum sp and Bacillus sp., respectively.
The inoculation of upland rice with multifunctional microorganism significantly affected the grain yield (Fig. 2D). Treatments 16 (36.85 grams), 19 (36.28 grams) and 27 (34.98 grams) provided the highest values and differed from the other treatments and the control. An increase of 27%, 25% and 20% in grain yield of upland rice was recorded for the above treatments in comparison to the control, respectively. These results were expected once the grain yield is a reflex of the yield components, which could be affected by root and shoots development (Nascente et al. 2013). Root and shoots biomass, number of panicles and 1000 grains weight was higher in upland rice plants treated with microorganisms of the treatments 16, 19 and 27 (Figs. 1 and 2). Besides, treatment 16 provided the highest significant accumulation of P, K, Ca, Mg and S in roots (Table 1), K and Ca in shoots (Table 2), and K, Ca, Mg and S in grains (Table 3). The treatment 19 provided the highest significant accumulation of P, K, Ca, Mg and S in roots, P, K, Ca and S in shoots, and K, Ca, Mg and S in seeds. The treatment 27 provided the highest accumulation of P, K, Ca, Mg and S in roots, P, K, Ca and S in shoots, and K, Ca and S in seeds. All these treatments (16, 19 and 27) provided more nutrients in upland rice plants (roots, shoots and seeds) than the control (Table 1 to 3). Beneficial microorganisms can also have indirect effect in plant development by increasing the availability of nutrients in the soil and improve the absorption and accumulation of nutrients within the plants (Pérez-García et al. 2011; Zhang et al. 2011; Nascente et al. 2017a, b). These results are reflex of the biochemical characteristics of the microorganisms, once microorganisms 16, 19 and 27 make nitrogen fixation, solubilise insoluble and organic phosphate, produce biofilm, indol acetic acid and siderophores. These characteristics improve plant development with positive effect on the grains yield, as observed in our trial.
Table 1
Phosphorus (P), potassium (K), calcium (Ca), Magnesium (Mg) and sulfur (S) accumulation in roots as a function of sole and combined microorganisms in upland rice plants, cultivar BRS A501 CL.
Treatments | P Root | K Root | Ca Root | Mg Root | S Root |
1 | 0.008b | 0.029a | 0.023b | 0.008b | 0.010c |
2 | 0.007b | 0.018b | 0.020b | 0.007b | 0.010c |
3 | 0.014a | 0.029a | 0.037a | 0.011a | 0.016c |
4 | 0.011a | 0.023a | 0.027b | 0.009b | 0.011c |
5 | 0.007b | 0.013b | 0.019b | 0.006b | 0.010c |
6 | 0.012a | 0.019b | 0.027b | 0.008b | 0.012c |
7 | 0.009b | 0.025a | 0.020b | 0.008b | 0.012c |
8 | 0.009b | 0.018b | 0.027b | 0.009b | 0.016c |
9 | 0.008b | 0.017b | 0.021b | 0.007b | 0.012c |
10 | 0.007b | 0.015b | 0.018b | 0.006b | 0.012c |
11 | 0.013a | 0.019b | 0.020b | 0.007b | 0.011c |
12 | 0.008b | 0.014b | 0.025b | 0.008b | 0.014c |
13 | 0.006b | 0.011b | 0.015b | 0.005b | 0.011c |
14 | 0.009b | 0.015b | 0.020b | 0.007b | 0.015c |
15 | 0.008b | 0.019b | 0.019b | 0.007b | 0.015c |
16 | 0.013a | 0.024a | 0.031a | 0.011a | 0.022a |
17 | 0.008b | 0.022ª | 0.021b | 0.007b | 0.018c |
18 | 0.009b | 0.018b | 0.022b | 0.008b | 0.017c |
19 | 0.015a | 0.022a | 0.030a | 0.011a | 0.022a |
20 | 0.013a | 0.018b | 0.024b | 0.008b | 0.017c |
21 | 0.005b | 0.017b | 0.014b | 0.005b | 0.014c |
22 | 0.012a | 0.026a | 0.026b | 0.010a | 0.024a |
23 | 0.006b | 0.013b | 0.015b | 0.005b | 0.014c |
24 | 0.003c | 0.009c | 0.008c | 0.003c | 0.008c |
25 | 0.009b | 0.015b | 0.019b | 0.006b | 0.016c |
26 | 0.009b | 0.024a | 0.022b | 0.008b | 0.020a |
27 | 0.011a | 0.031a | 0.032a | 0.012a | 0.026a |
28 | 0.012a | 0.028a | 0.032a | 0.011a | 0.030a |
29 | 0.007b | 0.014b | 0.016b | 0.006b | 0.015c |
* Treatments with the same letter do not differ from each other from the Scott-Knott test at p < 0.05. ** Treatments: 1- BRM 32114 (Serratia marcescens), 2-BRM 32110 (Bacillus toyonensis), 3- BRM 62389 (Phanerochaete australiani), 4 -BRM 53736 (Trichoderma koningiopsis), 5-AbV5 (Azospirillum brasilense), 6 -BRM 63574 (Azospirillum sp.), 7-BRM 63573 (Bacillus sp.), 8-BRM 32114 + BRM 32110, 9-BRM 32114 + AbV5, 10-BRM 32114 + BRM 53736, 11-BRM 32110 + AbV5, 12-BRM 32110 + BRM 53736, 13-AbV5 + BRM 53736, 14-BRM 63574 + BRM 63573, 15-BRM 63574 + AbV5, 16-BRM 63573 + AbV5, 17-BRM 63574 + BRM 32114, 18-BRM 63573 + BRM 32114, 19-BRM 63574 + BRM 32110, 20-BRM 63573 + BRM 32110, 21-BRM 63574 + BRM 53736, 22-BRM 63573 + BRM 53736, 23-BRM 62389 + BRM 63573, 24-BRM 62389 + BRM 63574, 25-BRM 62389 + AbV5, 26-BRM 62389 + BRM 53736, 27-BRM 62389 + BRM 32114, 28-BRM 62389 + BRM 32110, 29-control. |
Table 2
Phosphorus (P), potassium (K), calcium (Ca), Magnesium (Mg) and sulfur (S) accumulation in shoots as a function of sole and combined microorganisms in upland rice plants, cultivar BRS A501 CL.
Treatments | P Shoot | K Shoot | Ca Shoot | Mg Shoot | S Shoot |
1 | 0.010b | 0.315b | 0.265a | 0.083b | 0.043b |
2 | 0.009b | 0.400a | 0.223b | 0.063c | 0.050b |
3 | 0.014a | 0.405a | 0.247b | 0.066c | 0.063b |
4 | 0.007b | 0.328b | 0.214b | 0.069c | 0.043b |
5 | 0.011b | 0.341b | 0.179c | 0.040c | 0.049b |
6 | 0.010b | 0.336b | 0.273a | 0.073b | 0.053b |
7 | 0.010b | 0.316b | 0.180c | 0.044c | 0.060b |
8 | 0.010b | 0.330b | 0.216b | 0.052c | 0.057b |
9 | 0.009b | 0.236b | 0.167c | 0.052c | 0.036c |
10 | 0.009b | 0.275b | 0.200b | 0.069c | 0.042b |
11 | 0.009b | 0.358b | 0.190b | 0.054c | 0.046b |
12 | 0.007b | 0.228b | 0.274a | 0.096b | 0.038c |
13 | 0.013a | 0.409a | 0.448a | 0.127a | 0.078a |
14 | 0.007b | 0.281b | 0.156c | 0.043c | 0.035c |
15 | 0.008b | 0.307b | 0.238b | 0.067c | 0.056b |
16 | 0.010b | 0.394a | 0.289a | 0.096b | 0.061b |
17 | 0.010b | 0.245b | 0.177c | 0.047c | 0.050b |
18 | 0.009b | 0.304b | 0.151c | 0.039c | 0.042b |
19 | 0.012a | 0.391a | 0.322a | 0.084b | 0.072a |
20 | 0.009b | 0.279b | 0.219b | 0.054c | 0.053b |
21 | 0.009b | 0.295b | 0.205b | 0.046c | 0.055b |
22 | 0.010b | 0.336b | 0.181c | 0.061c | 0.047b |
23 | 0.012a | 0.294b | 0.195b | 0.050c | 0.056b |
24 | 0.006b | 0.181c | 0.105d | 0.031c | 0.027c |
25 | 0.010b | 0.289b | 0.240b | 0.064c | 0.061b |
26 | 0.008b | 0.317b | 0.278a | 0.087b | 0.055b |
27 | 0.015a | 0.409a | 0.263a | 0.064c | 0.072a |
28 | 0.009b | 0.232b | 0.239b | 0.078b | 0.049b |
29 | 0.005b | 0.227b | 0.223b | 0.079b | 0.037c |
* Treatments with the same letter do not differ from each other from the Scott-Knott test at p < 0.05. ** Treatments: 1- BRM 32114 (Serratia marcescens), 2-BRM 32110 (Bacillus toyonensis), 3- BRM 62389 (Phanerochaete australiani), 4 -BRM 53736 (Trichoderma koningiopsis), 5-AbV5 (Azospirillum brasilense), 6 -BRM 63574 (Azospirillum sp.), 7-BRM 63573 (Bacillus sp.), 8-BRM 32114 + BRM 32110, 9-BRM 32114 + AbV5, 10-BRM 32114 + BRM 53736, 11-BRM 32110 + AbV5, 12-BRM 32110 + BRM 53736, 13-AbV5 + BRM 53736, 14-BRM 63574 + BRM 63573, 15-BRM 63574 + AbV5, 16-BRM 63573 + AbV5, 17-BRM 63574 + BRM 32114, 18-BRM 63573 + BRM 32114, 19-BRM 63574 + BRM 32110, 20-BRM 63573 + BRM 32110, 21-BRM 63574 + BRM 53736, 22-BRM 63573 + BRM 53736, 23-BRM 62389 + BRM 63573, 24-BRM 62389 + BRM 63574, 25-BRM 62389 + AbV5, 26-BRM 62389 + BRM 53736, 27-BRM 62389 + BRM 32114, 28-BRM 62389 + BRM 32110, 29-control. |
Table 3
Phosphorus (P), potassium (K), calcium (Ca), Magnesium (Mg) and sulfur (S) accumulation in grains as a function of sole and combined microorganisms in upland rice plants, cultivar BRS A501 CL.
Treatments | P Seed | K Seed | Ca Seed | Mg Seed | S seed |
1 | 0.060a | 0.088c | 0.008b | 0.024c | 0.047b |
2 | 0.068a | 0.093c | 0.009b | 0.027c | 0.050b |
3 | 0.068a | 0.098c | 0.009b | 0.028c | 0.051b |
4 | 0.067a | 0.090c | 0.008b | 0.027c | 0.051b |
5 | 0.056a | 0.078c | 0.007b | 0.023c | 0.041b |
6 | 0.064a | 0.094c | 0.009b | 0.026c | 0.052b |
7 | 0.064a | 0.084c | 0.008b | 0.025c | 0.048b |
8 | 0.061a | 0.137b | 0.034b | 0.030c | 0.051b |
9 | 0.011b | 0.280b | 0.201a | 0.061b | 0.043b |
10 | 0.010b | 0.319b | 0.280a | 0.085b | 0.055b |
11 | 0.011b | 0.436a | 0.234a | 0.066b | 0.056b |
12 | 0.008b | 0.281b | 0.333a | 0.117a | 0.046b |
13 | 0.010b | 0.298b | 0.321a | 0.086b | 0.061a |
14 | 0.009b | 0.389a | 0.230a | 0.061b | 0.049b |
15 | 0.009b | 0.367a | 0.283a | 0.080b | 0.067a |
16 | 0.011b | 0.438a | 0.328a | 0.108a | 0.068a |
17 | 0.012b | 0.377a | 0.241a | 0.064b | 0.070a |
18 | 0.011b | 0.365a | 0.188a | 0.048c | 0.052b |
19 | 0.013b | 0.436a | 0.361a | 0.096a | 0.080a |
20 | 0.011b | 0.333b | 0.261a | 0.064b | 0.063a |
21 | 0.009b | 0.305b | 0.212a | 0.047c | 0.057b |
22 | 0.011b | 0.379a | 0.205a | 0.069b | 0.053b |
23 | 0.013b | 0.333b | 0.226a | 0.058b | 0.063a |
24 | 0.007b | 0.239b | 0.136b | 0.043c | 0.035b |
25 | 0.012b | 0.326b | 0.269a | 0.071b | 0.069a |
26 | 0.009b | 0.366a | 0.305a | 0.095a | 0.063a |
27 | 0.016b | 0.452a | 0.290a | 0.070b | 0.080a |
28 | 0.010b | 0.263b | 0.272a | 0.088b | 0.056b |
29 | 0.007b | 0.283b | 0.274a | 0.096a | 0.047b |
* Treatments with the same letter do not differ from each other from the Scott-Knott test at p < 0.05. ** Treatments: 1- BRM 32114 (Serratia marcescens), 2-BRM 32110 (Bacillus toyonensis), 3- BRM 62389 (Phanerochaete australiani), 4 -BRM 53736 (Trichoderma koningiopsis), 5-AbV5 (Azospirillum brasilense), 6 -BRM 63574 (Azospirillum sp.), 7-BRM 63573 (Bacillus sp.), 8-BRM 32114 + BRM 32110, 9-BRM 32114 + AbV5, 10-BRM 32114 + BRM 53736, 11-BRM 32110 + AbV5, 12-BRM 32110 + BRM 53736, 13-AbV5 + BRM 53736, 14-BRM 63574 + BRM 63573, 15-BRM 63574 + AbV5, 16-BRM 63573 + AbV5, 17-BRM 63574 + BRM 32114, 18-BRM 63573 + BRM 32114, 19-BRM 63574 + BRM 32110, 20-BRM 63573 + BRM 32110, 21-BRM 63574 + BRM 53736, 22-BRM 63573 + BRM 53736, 23-BRM 62389 + BRM 63573, 24-BRM 62389 + BRM 63574, 25-BRM 62389 + AbV5, 26-BRM 62389 + BRM 53736, 27-BRM 62389 + BRM 32114, 28-BRM 62389 + BRM 32110, 29-control. |
Our results allow inferring that the use of multifunctional microorganisms in the rice crop is of essential importance as it promotes increases in the crop grain yield (Araujo et al. 2021). When the microorganisms were applied singly, the effect on grain yield was lower than in the coinoculation. Therefore, we could observe that microorganisms had a synergistic effect in upland rice grain yield.
With the application of principal component analysis (PCA), it can be seen that the variability of treatments with isolated and combined microorganisms in relation to the number of panicles, number of grains per panicle, mass of a thousand grains, productivity per pot, dry mass and nutrient content of root, shoots and seeds of upland rice plants treated with multifunctional microorganisms was best described by three principal components (PCs), responsible for 77% of the variation in the data, i.e. PC1 (42.3%), PC2 (22%) and PC2 (11%) (Fig. 3). The factor map (biplot) shows groups of variables denoting positive and negative correlations with each PC.
PC1 was negatively correlated with all analyzed variables (Fig. 3B). On the other hand, PC2 was positively correlated with NP, mass of 1000 grains, yield per pot, root and shoot dry mass, P and K content in shoots, P, K, Ca and Mg content in roots and P content in seeds (Fig. 3C). PC2 was negatively correlated with number of grains per panicle (NGP), S, Ca and Mg content in shoots, S content in roots and K, Ca, Mg and S content in seeds. PC3 (Fig. 3D) was positively correlated with NGP, productivity per pot, shoot dry mass, P, K, Mg, Ca and S content in shoots, P, Ca and S content in seeds. Finally, PC3 was negatively correlated with NP, mass of 1000 grains, P, K, Mg, Ca and S content in the roots, K and Mg content in the seeds.
Based on the representational quality of treatments with microorganisms alone and in combination for the variables analyzed in PC1 x PC2, isolates 1, 2, 3, 4, 6 and 8 (Fig. 3A), obtained the highest positive correlation for the content of P in the seed (Fig. 7B). The variables number of panicles (NP), weight of 1000 grains, productivity per pot, root and shoot weights, and K and Mg content in the roots, and S content in the shoot were positively correlated with treatment 27. Treatments 16 and 19 were correlated positively to NGP, S content in the root and seeds, Ca and Mg content in the shoot. Treatments 26, 11 and 15 were positively correlated with the variables NGP, content of K, Mg and Ca in the seeds. The remaining treatments did not correlate positively with any of the analyzed variables.
Based on the representational quality of treatments with microorganisms alone and in combination for the variables analyzed in PC1 x PC3, isolate 13 (Fig. 3C), obtained the highest positive correlation for shoot mass, P, K, Mg, Ca and S in shoots and S content in seeds (Fig. 3D). The variables NP, mass of 1000 grains, productivity per pot, root mass, and P, K, Mg, Ca and S content in the roots were positively correlated with treatments 3, 16, 19 and 27. Treatments 8, 12, 20 and 26 correlated positively with the variables NGP, P, K, Mg and Ca content in the seeds. The remaining treatments did not correlate positively with any of the analyzed variables.
Our results show that the use of multifunctional microorganisms could be an important strategy to improve rice grain yield. We could see that these microorganisms improved shoots and roots biomass, yield components and grain yield of upland rice. Further, field trials should be done using these microorganisms to confirm these good results achieved in controlled situation.